SEAT WARMER SYSTEM DOES NOT OPERATE [SEAT WARMER SYSTEM]

id0903m2970800


Front Seat Side


With seat ventilation system

Description
The seat warmer does not warm up even if the seat warmer switch is turned on.
Possible Causes
•  Seat warmer switch malfunction
•  Front seat warmer control unit power supply circuit malfunction
―  Short to ground in wiring harness between the following terminals:
•  SEAT WARM 20 A fuse and front seat warmer control unit terminal C
•  SEAT WARM 20 A fuse and front seat warmer control unit terminal D
•  C/U IG1 15 A fuse and front seat warmer control unit terminal I
―  SEAT WARM 20 A fuse malfunction
―  C/U IG1 15 A fuse malfunction
―  Open circuit in wiring harness between the following terminals:
•  SEAT WARM 20 A fuse and front seat warmer control unit terminal C
•  SEAT WARM 20 A fuse and front seat warmer control unit terminal D
•  C/U IG1 15 A fuse and front seat warmer control unit terminal I
•  Open circuit in wiring harness between the following terminals:
―  Front seat warmer control unit terminal S and body ground
―  Front seat warmer control unit terminal T and body ground
•  Malfunction in wiring harness between front seat warmer control unit terminal F and front climate control unit terminal 1X
―  Short to ground in wiring harness between front seat warmer control unit terminal F and front climate control unit terminal 1X
―  Open circuit in wiring harness between front seat warmer control unit terminal F and front climate control unit terminal 1X
•  Front climate control unit malfunction
•  Seat warmer unit malfunction
•  Front seat warmer control unit malfunction
•  Connector poor contact or terminal damage

Diagnostic Procedure

Step

Inspection

Action
1
DETERMINE MALFUNCTION SYMPTOM
•  Operate the seat warmer switches on the driver and passenger sides to turn on the seat warmer system for the driver and passenger sides.
•  Does a malfunction occur with the seat warmer system on both sides?
Yes
Go to Step 8.
No
Go to the next step.
2
INSPECT FRONT SEAT WARMER CONTROL UNIT CONNECTOR AND SEAT WARMER UNIT CONNECTOR
•  Switch the ignition OFF.
•  Disconnect the negative battery terminal.
•  Disconnect the front seat warmer control unit connector and the seat warmer unit connector on the side which does not operate.
•  Inspect the connector engagement and connection condition, and inspect the terminals for damage, deformation, corrosion, or disconnection.
•  Is the connector normal?
Yes
Go to the next step.
No
Repair or replace the connector, then go to Step 10.
3
VERIFY IF MALFUNCTION CAUSE IS FRONT SEAT WARMER CONTROL UNIT POWER SUPPLY CIRCUIT
•  Verify that the front seat warmer control unit connector is disconnected.
•  Connect the negative battery terminal.
•  Switch the ignition ON (engine off or on).
•  Measure the voltage at the following terminals (vehicle wiring harness side):
―  Front seat warmer control unit terminal C
―  Front seat warmer control unit terminal D
―  Front seat warmer control unit terminal I
•  Is the voltage B+?
Yes
Go to the next step.
No
Inspect the SEAT WARM 20 A fuse and C/U IG1 15 A fuse.
If the fuse is blown:
•  Refer to the wiring diagram and verify if there is a common wiring harness between the following terminals:
―  SEAT WARM 20 A fuse and front seat warmer control unit terminal C
―  SEAT WARM 20 A fuse and front seat warmer control unit terminal D
―  C/U IG1 15 A fuse and front seat warmer control unit terminal I
If there is a common connector:
•  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.
•  Repair or replace the malfunctioning location.
If there is no common connector:
•  Repair or replace the wiring harness which is shorted to ground.
•  Replace the fuse.
If the fuse is damaged:
•  Replace the fuse.
If the fuse is normal:
•  Refer to the wiring diagram and verify if there is a common wiring harness between the following terminals:
―  SEAT WARM 20 A fuse and front seat warmer control unit terminal C
―  SEAT WARM 20 A fuse and front seat warmer control unit terminal D
―  C/U IG1 15 A fuse and front seat warmer control unit terminal I
If there is a common connector:
•  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for an open circuit to determine the malfunctioning location.
•  Repair or replace the malfunctioning location.
If there is no common connector:
•  Repair or replace the wiring harness which has an open circuit.
Go to Step 10.
4
VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS BETWEEN FRONT SEAT WARMER CONTROL UNIT AND BODY GROUND
•  Switch the ignition OFF (LOCK).
•  Verify that the front seat warmer control unit connector is disconnected.
•  Inspect for continuity between the following terminals (vehicle wiring harness side) and body ground:
―  Front seat warmer control unit terminal S
―  Front seat warmer control unit terminal T
•  Is there continuity?
Yes
Go to the next step.
No
•  Refer to the wiring diagram and verify if there is a common connector between the following terminals and body ground:
―  Front seat warmer control unit terminal S
―  Front seat warmer control unit terminal T
If there is a common connector:
•  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for an open circuit to determine the malfunctioning location.
•  Repair or replace the malfunctioning location.
If there is no common connector:
•  Repair or replace the wiring harness which has an open circuit.
•  Go to Step 10.
5
VERIFY IF MALFUNCTION CAUSE IS SHORT CIRCUIT TO GROUND IN WIRING HARNESS BETWEEN FRONT SEAT WARMER CONTROL UNIT AND FRONT CLIMATE CONTROL UNIT
•  Verify that the front seat warmer control unit connector is disconnected.
•  Disconnect the front climate control unit connector.
•  Inspect for continuity between front seat warmer control unit terminal F (vehicle wiring harness side) and body ground.
•  Is there continuity?
Yes
•  Refer to the wiring diagram and verify if there is a common connector between front seat warmer control unit terminal F and front climate control unit terminal 1X.
If there is a common connector:
―  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.
―  Repair or replace the malfunctioning location.
If there is no common connector:
―  Repair or replace the wiring harness which is shorted to ground.
•  Go to Step 10.
No
Go to the next step.
6
VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS BETWEEN FRONT SEAT WARMER CONTROL UNIT AND FRONT CLIMATE CONTROL UNIT
•  Verify that the front seat warmer control unit connector and the front climate control unit connector are disconnected.
•  Inspect the wiring harness for continuity between front seat warmer control unit terminal F and front climate control unit terminal 1X (vehicle wiring harness side).
•  Is there continuity?
Yes
Go to the next step.
No
•  Refer to the wiring diagram and verify if there is a common connector between front seat warmer control unit terminal F and front climate control unit terminal 1X.
If there is a common connector:
―  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for an open circuit to determine the malfunctioning location.
―  Repair or replace the malfunctioning location.
If there is no common connector:
―  Repair or replace the wiring harness which has an open circuit.
•  Go to Step 10.
7
VERIFY IF MALFUNCTION CAUSE IS SEAT WARMER UNIT
•  Inspect the seat warmer unit on the side which has a malfunction.
•  Is the seat warmer unit normal?
Yes
Go to the next step.
No
Replace the seat warmer unit (front seat cushion pad or front seat back pad) which has a malfunction, then go to Step 10.
(See FRONT SEAT BACK TRIM REMOVAL/INSTALLATION.)
8
DETERMINE IF MALFUNCTION CAUSE IS FRONT CLIMATE CONTROL UNIT
•  Inspect the front climate control unit.
•  Is the front climate control unit normal?
Yes
Go to the next step.
No
Replace the front climate control unit, then go to Step 10.
(See FRONT CLIMATE CONTROL UNIT REMOVAL/INSTALLATION.)
9
DETERMINE IF MALFUNCTION CAUSE IS FRONT SEAT WARMER CONTROL UNIT
•  Reconnect all the disconnected connectors.
•  Connect the negative battery terminal.
•  Switch the ignition ON (engine off or on).
•  Operate the seat warmer switch to turn on the seat warmer system.
•  Does the seat warmer system operate normally?
Yes
Go to the next step.
No
Replace the front seat warmer control unit, then go to the next step.
(See FRONT SEAT WARMER CONTROL UNIT REMOVAL/INSTALLATION.)
10
VERIFY IF MALFUNCTION CAUSE IS CORRECTED
•  Operate the seat warmer switch to turn on the seat warmer system.
•  Does the seat warmer system operate normally?
Yes
Troubleshooting completed. (Explain the contents of the servicing to the customer.)
No
Verify the malfunction symptom in the symptom troubleshooting chart and perform the other applicable malfunction diagnosis.
(See SYMPTOM TROUBLESHOOTING [SEAT WARMER SYSTEM].)


Without seat ventilation system

Description
The seat warmer does not warm up even if the seat warmer switch is turned on.
Possible Causes
•  Front seat warmer switch malfunction
•  Front seat warmer control unit power supply circuit malfunction
―  Short to ground in wiring harness between the following terminals:
•  SEAT WARM 20 A fuse and front seat warmer control unit terminal O
•  SEAT WARM 20 A fuse and front seat warmer control unit terminal M
•  C/U IG1 15 A fuse and front seat warmer control unit terminal A
―  SEAT WARM 20 A fuse malfunction
―  C/U IG1 15 A fuse malfunction
―  Open circuit in wiring harness between the following terminals:
•  SEAT WARM 20 A fuse and front seat warmer control unit terminal O
•  SEAT WARM 20 A fuse and front seat warmer control unit terminal M
•  C/U IG1 15 A fuse and front seat warmer control unit terminal A
•  Open circuit in wiring harness between the following terminals:
―  Front seat warmer control unit terminal L and body ground
―  Front seat warmer control unit terminal N and body ground
•  Malfunction in wiring harness between front seat warmer control unit terminal J and front climate control unit terminal 1X
―  Short to ground in wiring harness between front seat warmer control unit terminal J and front climate control unit terminal 1X
―  Open circuit in wiring harness between front seat warmer control unit terminal J and front climate control unit terminal 1X
•  Front climate control unit malfunction
•  Front seat warmer unit malfunction
•  Front seat warmer control unit malfunction
•  Connector poor contact or terminal damage

Diagnostic Procedure

Step

Inspection

Action
1
DETERMINE MALFUNCTION SYMPTOM
•  Operate the seat warmer switches on the driver and passenger sides to turn on the seat warmer system for the driver and passenger sides.
•  Does a malfunction occur with the seat warmer system on both sides?
Yes
Go to Step 8.
No
Go to the next step.
2
INSPECT FRONT SEAT WARMER CONTROL UNIT CONNECTOR AND SEAT WARMER UNIT CONNECTOR
•  Switch the ignition OFF.
•  Disconnect the negative battery terminal.
•  Disconnect the front seat warmer control unit connector and the seat warmer unit connector on the side which does not operate.
•  Inspect the connector engagement and connection condition, and inspect the terminals for damage, deformation, corrosion, or disconnection.
•  Is the connector normal?
Yes
Go to the next step.
No
Repair or replace the connector, then go to Step 10.
3
VERIFY IF MALFUNCTION CAUSE IS FRONT SEAT WARMER CONTROL UNIT POWER SUPPLY CIRCUIT
•  Verify that the front seat warmer control unit connector is disconnected.
•  Connect the negative battery terminal.
•  Switch the ignition ON (engine off or on).
•  Measure the voltage at the following terminals (vehicle wiring harness side):
―  Front seat warmer control unit terminal O
―  Front seat warmer control unit terminal M
―  Front seat warmer control unit terminal A
•  Is the voltage B+?
Yes
Go to the next step.
No
Inspect the SEAT WARM 20 A fuse and C/U IG1 15 A fuse.
If the fuse is blown:
•  Refer to the wiring diagram and verify if there is a common wiring harness between the following terminals:
―  SEAT WARM 20 A fuse and front seat warmer control unit terminal O
―  SEAT WARM 20 A fuse and front seat warmer control unit terminal M
―  C/U IG1 15 A fuse and front seat warmer control unit terminal A
If there is a common connector:
•  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.
•  Repair or replace the malfunctioning location.
If there is no common connector:
•  Repair or replace the wiring harness which is shorted to ground.
•  Replace the fuse.
If the fuse is damaged:
•  Replace the fuse.
If the fuse is normal:
•  Refer to the wiring diagram and verify if there is a common wiring harness between the following terminals:
―  SEAT WARM 20 A fuse and front seat warmer control unit terminal O
―  SEAT WARM 20 A fuse and front seat warmer control unit terminal M
―  C/U IG1 15 A fuse and front seat warmer control unit terminal A
If there is a common connector:
•  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for an open circuit to determine the malfunctioning location.
•  Repair or replace the malfunctioning location.
If there is no common connector:
•  Repair or replace the wiring harness which has an open circuit.
Go to Step 10.
4
VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS BETWEEN FRONT SEAT WARMER CONTROL UNIT AND BODY GROUND
•  Switch the ignition OFF (LOCK).
•  Verify that the front seat warmer control unit connector is disconnected.
•  Inspect for continuity between the following terminals (vehicle wiring harness side) and body ground:
―  Front seat warmer control unit terminal L
―  Front seat warmer control unit terminal N
•  Is there continuity?
Yes
Go to the next step.
No
•  Refer to the wiring diagram and verify if there is a common connector between the following terminals and body ground:
―  Front seat warmer control unit terminal L
―  Front seat warmer control unit terminal N
If there is a common connector:
•  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for an open circuit to determine the malfunctioning location.
•  Repair or replace the malfunctioning location.
If there is no common connector:
•  Repair or replace the wiring harness which has an open circuit.
•  Go to Step 10.
5
VERIFY IF MALFUNCTION CAUSE IS SHORT CIRCUIT TO GROUND IN WIRING HARNESS BETWEEN FRONT SEAT WARMER CONTROL UNIT AND FRONT CLIMATE CONTROL UNIT
•  Verify that the front seat warmer control unit connector is disconnected.
•  Disconnect the front climate control unit connector.
•  Inspect for continuity between front seat warmer control unit terminal J (vehicle wiring harness side) and body ground.
•  Is there continuity?
Yes
•  Refer to the wiring diagram and verify if there is a common connector between front seat warmer control unit terminal J and front climate control unit terminal 1X.
If there is a common connector:
―  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.
―  Repair or replace the malfunctioning location.
If there is no common connector:
―  Repair or replace the wiring harness which is shorted to ground.
•  Go to Step 10.
No
Go to the next step.
6
VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS BETWEEN FRONT SEAT WARMER CONTROL UNIT AND FRONT CLIMATE CONTROL UNIT
•  Verify that the front seat warmer control unit connector and the front climate control unit connector are disconnected.
•  Inspect the wiring harness for continuity between front seat warmer control unit terminal J and front climate control unit terminal 1X (vehicle wiring harness side).
•  Is there continuity?
Yes
Go to the next step.
No
•  Refer to the wiring diagram and verify if there is a common connector between front seat warmer control unit terminal J and front climate control unit terminal 1X.
If there is a common connector:
―  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for an open circuit to determine the malfunctioning location.
―  Repair or replace the malfunctioning location.
If there is no common connector:
―  Repair or replace the wiring harness which has an open circuit.
•  Go to Step 10.
7
VERIFY IF MALFUNCTION CAUSE IS SEAT WARMER UNIT
•  Inspect the seat warmer unit on the side which has a malfunction.
•  Is the seat warmer unit normal?
Yes
Go to the next step.
No
Replace the seat warmer unit (front seat cushion pad or front seat back pad) which has a malfunction, then go to Step 10.
(See FRONT SEAT BACK TRIM REMOVAL/INSTALLATION.)
8
DETERMINE IF MALFUNCTION CAUSE IS FRONT CLIMATE CONTROL UNIT
•  Inspect the front climate control unit.
•  Is the front climate control unit normal?
Yes
Go to the next step.
No
Replace the front climate control unit, then go to Step 10.
(See REAR CLIMATE CONTROL UNIT REMOVAL/INSTALLATION.)
9
DETERMINE IF MALFUNCTION CAUSE IS FRONT SEAT WARMER CONTROL UNIT
•  Reconnect all the disconnected connectors.
•  Connect the negative battery terminal.
•  Switch the ignition ON (engine off or on).
•  Operate the seat warmer switch to turn on the seat warmer system.
•  Does the seat warmer system operate normally?
Yes
Go to the next step.
No
Replace the front seat warmer control unit, then go to the next step.
(See FRONT SEAT WARMER CONTROL UNIT REMOVAL/INSTALLATION.)
10
VERIFY IF MALFUNCTION CAUSE IS CORRECTED
•  Operate the seat warmer switch to turn on the seat warmer system.
•  Does the seat warmer system operate normally?
Yes
Troubleshooting completed. (Explain the contents of the servicing to the customer.)
No
Verify the malfunction symptom in the symptom troubleshooting chart and perform the other applicable malfunction diagnosis.
(See SYMPTOM TROUBLESHOOTING [SEAT WARMER SYSTEM].)


Second-row Seat Side


Bench seat type or captain seat type (without seat ventilation system)

Description
The seat warmer does not warm up even if the seat warmer switch is turned on.
Possible Causes
•  Second-row seat warmer switch malfunction
•  Second-row seat warmer control unit power supply circuit malfunction
―  Short to ground in wiring harness between the following terminals:
•  R.SEAT W 20 A fuse and second-row seat warmer control unit terminal O
•  R.SEAT W 20 A fuse and second-row seat warmer control unit terminal M
―  R.SEAT W 20 A fuse malfunction
―  Open circuit in wiring harness between the following terminals:
•  R.SEAT W 20 A fuse and second-row seat warmer control unit terminal O
•  R.SEAT W 20 A fuse and second-row seat warmer control unit terminal M
―  Short to ground in wiring harness between the following terminals:
•  HAZARD 25 A fuse and front body control module (FBCM) terminal 1A
•  HAZARD 25 A fuse and front body control module (FBCM) terminal 1B
―  HAZARD 25 A fuse malfunction
―  Open circuit in wiring harness between the following terminals:
•  HAZARD 25 A fuse and front body control module (FBCM) terminal 1A
•  HAZARD 25 A fuse and front body control module (FBCM) terminal 1B
―  Short to ground in wiring harness between front body control module (FBCM) terminal 1C and second-row seat warmer control unit terminal A
―  Open circuit in wiring harness between front body control module (FBCM) terminal 1C and second-row seat warmer control unit terminal A
―  Front body control module (FBCM) malfunction
•  Open circuit in wiring harness between the following terminals:
―  Second-row seat warmer control unit terminal L and body ground
―  Second-row seat warmer control unit terminal N and body ground
•  Malfunction in wiring harness between second-row seat warmer control unit terminal J and rear climate control unit terminal T
―  Short to ground in wiring harness between second-row seat warmer control unit terminal J and rear climate control unit terminal T
―  Open circuit in wiring harness between second-row seat warmer control unit terminal J and rear climate control unit terminal T
•  Rear climate control unit malfunction
•  Second-row seat warmer unit malfunction
•  Second-row seat warmer control unit malfunction
•  Connector poor contact or terminal damage

*1  :Captain seat type (without seat ventilation system)
*2  :Bench seat type

Diagnostic Procedure

Step

Inspection

Action
1
DETERMINE MALFUNCTION SYMPTOM
•  Operate the seat warmer switches on the driver and passenger sides to turn on the seat warmer system for the driver and passenger sides.
•  Does a malfunction occur with the seat warmer system on both sides?
Yes
Go to Step 11.
No
Go to the next step.
2
INSPECT SECOND-ROW SEAT WARMER CONTROL UNIT CONNECTOR AND SEAT WARMER UNIT CONNECTOR
•  Switch the ignition OFF.
•  Disconnect the negative battery terminal.
•  Disconnect the second-row seat warmer control unit connector and the second-row seat warmer unit connector on the side which does not operate.
•  Inspect the connector engagement and connection condition, and inspect the terminals for damage, deformation, corrosion, or disconnection.
•  Is the connector normal?
Yes
Go to the next step.
No
Repair or replace the connector, then go to Step 14.
3
VERIFY IF MALFUNCTION CAUSE IS SECOND-ROW SEAT WARMER CONTROL UNIT POWER SUPPLY CIRCUIT
•  Verify that the second-row seat warmer control unit connector is disconnected.
•  Connect the negative battery terminal.
•  Switch the ignition ON (engine off or on).
•  Measure the voltage at the following terminals (vehicle wiring harness side):
―  Second-row seat warmer control unit terminal O
―  Second-row seat warmer control unit terminal M
•  Is the voltage B+?
Yes
Go to the next step.
No
Inspect the R.SEAT W 20 A fuse.
If the fuse is blown:
•  Refer to the wiring diagram and verify if there is a common wiring harness between the following terminals:
―  R.SEAT W 20 A fuse and front seat warmer control unit terminal O
―  R.SEAT W 20 A fuse and front seat warmer control unit terminal M
If there is a common connector:
•  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.
•  Repair or replace the malfunctioning location.
If there is no common connector:
•  Repair or replace the wiring harness which is shorted to ground.
•  Replace the fuse.
If the fuse is damaged:
•  Replace the fuse.
If the fuse is normal:
•  Refer to the wiring diagram and verify if there is a common wiring harness between the following terminals:
―  R.SEAT W 20 A fuse and second-row seat warmer control unit terminal O
―  R.SEAT W 20 A fuse and second-row seat warmer control unit terminal M
If there is a common connector:
•  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for an open circuit to determine the malfunctioning location.
•  Repair or replace the malfunctioning location.
If there is no common connector:
•  Repair or replace the wiring harness which has an open circuit.
Go to Step 14.
4
VERIFY IF MALFUNCTION CAUSE IS SECOND-ROW SEAT WARMER CONTROL UNIT POWER SUPPLY CIRCUIT
•  Switch the ignition OFF.
•  Disconnect the negative battery terminal.
•  Disconnect the front body control module (FBCM) connector.
•  Connect the negative battery terminal.
•  Switch the ignition ON (engine off or on).
•  Measure the voltage at the following terminals (vehicle wiring harness side).
―  Front body control module (FBCM) terminal 1A
―  Front body control module (FBCM) terminal 1B
•  Is the voltage B+?
Yes
Go to the next step.
No
Inspect the HAZARD 25 A fuse.
If the fuse is blown:
•  Refer to the wiring diagram and verify if there is a common wiring harness between the following terminals:
―  HAZARD 25 A fuse and front body control module (FBCM) terminal 1A
―  HAZARD 25 A fuse and front body control module (FBCM) terminal 1B
If there is a common connector:
•  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.
•  Repair or replace the malfunctioning location.
If there is no common connector:
•  Repair or replace the wiring harness which is shorted to ground.
•  Replace the fuse.
If the fuse is damaged:
•  Replace the fuse.
If the fuse is normal:
•  Refer to the wiring diagram and verify if there is a common wiring harness between the following terminals:
―  HAZARD 25 A fuse and front body control module (FBCM) terminal 1A
―  HAZARD 25 A fuse and front body control module (FBCM) terminal 1B
If there is a common connector:
•  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for an open circuit to determine the malfunctioning location.
•  Repair or replace the malfunctioning location.
If there is no common connector:
•  Repair or replace the wiring harness which has an open circuit.
Go to Step 14.
5
VERIFY IF MALFUNCTION CAUSE IS SHORT CIRCUIT TO GROUND IN WIRING HARNESS BETWEEN SECOND-ROW SEAT WARMER CONTROL UNIT AND FRONT BODY CONTROL MODULE (FBCM)
•  Switch the ignition OFF.
•  Disconnect the negative battery terminal.
•  Verify that the second-row seat warmer control unit connector and the front body control module (FBCM) connector are disconnected.
•  Inspect for continuity between front body control module (FBCM) terminal 1C (vehicle wiring harness side) and body ground.
•  Is there continuity?
Yes
•  Refer to the wiring diagram and verify if there is a common connector between front body control module (FBCM) terminal 1C and second-row seat warmer control unit terminal A.
If there is a common connector:
―  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.
―  Repair or replace the malfunctioning location.
If there is no common connector:
―  Repair or replace the wiring harness which is shorted to ground.
•  Go to Step 14.
No
Go to the next step.
6
VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS BETWEEN SECOND-ROW SEAT WARMER CONTROL UNIT AND FRONT BODY CONTROL MODULE (FBCM)
•  Verify that the second-row seat warmer control unit connector and the front body control module (FBCM) connector are disconnected.
•  Inspect the wiring harness for continuity between front body control module (FBCM) terminal 1C (vehicle wiring harness side) and second-row seat warmer control unit terminal A (vehicle wiring harness side).
•  Is there continuity?
Yes
Go to the next step.
No
•  Refer to the wiring diagram and verify if there is a common connector between front body control module (FBCM) terminal 1C and second-row seat warmer control unit terminal A.
If there is a common connector:
―  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for an open circuit to determine the malfunctioning location.
―  Repair or replace the malfunctioning location.
If there is no common connector:
―  Repair or replace the wiring harness which has an open circuit.
•  Go to Step 14.
7
VERIFY IF MALFUNCTION CAUSE IS SECOND-ROW SEAT WARMER CONTROL UNIT POWER SUPPLY CIRCUIT
•  Verify that the second-row seat warmer control unit connector is disconnected.
•  Connect the front body control module (FBCM) terminal.
•  Connect the negative battery terminal.
•  Switch the ignition ON (engine off or on).
•  Measure the voltage at the following terminals (vehicle wiring harness side).
―  Second-row seat warmer control unit terminal A
•  Is the voltage B+?
Yes
Go to the next step.
No
Replace the front body control module (FBCM) which has a malfunction, then go to Step 14.
(See FRONT BODY CONTROL MODULE (FBCM) REMOVAL/INSTALLATION.)
8
VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS BETWEEN SECOND-ROW SEAT WARMER CONTROL UNIT AND BODY GROUND
•  Switch the ignition OFF.
•  Disconnect the negative battery terminal.
•  Verify that the second-row seat warmer control unit connector is disconnected.
•  Inspect for continuity between the following terminals (vehicle wiring harness side) and body ground.
―  Second-row seat warmer control unit terminal N
―  Second-row seat warmer control unit terminal L
•  Is there continuity?
Yes
Go to the next step.
No
•  Refer to the wiring diagram and verify if there is a common connector between the following terminals and body ground.
―  Second-row seat warmer control unit terminal N
―  Second-row seat warmer control unit terminal L
If there is a common connector:
•  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for an open circuit to determine the malfunctioning location.
•  Repair or replace the malfunctioning location.
If there is no common connector:
•  Repair or replace the wiring harness which has an open circuit.
•  Go to Step 14.
9
VERIFY IF MALFUNCTION CAUSE IS SHORT CIRCUIT TO GROUND IN WIRING HARNESS BETWEEN SECOND-ROW SEAT WARMER CONTROL UNIT AND REAR CLIMATE CONTROL UNIT
•  Verify that the second-row seat warmer control unit connector is disconnected.
•  Disconnect the rear climate control unit connector.
•  Inspect for continuity between second-row seat warmer control unit terminal J (vehicle wiring harness side) and body ground.
•  Is there continuity?
Yes
•  Refer to the wiring diagram and verify if there is a common connector between second-row seat warmer control unit terminal J and rear climate control unit terminal T.
If there is a common connector:
―  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.
―  Repair or replace the malfunctioning location.
If there is no common connector:
―  Repair or replace the wiring harness which is shorted to ground.
•  Go to Step 14.
No
Go to the next step.
10
VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS BETWEEN SECOND-ROW SEAT WARMER CONTROL UNIT AND REAR CLIMATE CONTROL UNIT
•  Verify that the second-row seat warmer control unit connector and the rear climate control unit connector are disconnected.
•  Inspect the wiring harness for continuity between second-row seat warmer control unit terminal J and rear climate control unit terminal T (vehicle wiring harness side).
•  Is there continuity?
Yes
Go to the next step.
No
•  Refer to the wiring diagram and verify if there is a common connector between second-row seat warmer control unit terminal J and rear climate control unit terminal T.
If there is a common connector:
―  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for an open circuit to determine the malfunctioning location.
―  Repair or replace the malfunctioning location.
If there is no common connector:
―  Repair or replace the wiring harness which has an open circuit.
•  Go to Step 14.
11
VERIFY IF MALFUNCTION CAUSE IS SEAT WARMER UNIT
•  Inspect the second-row seat warmer unit on the side which has a malfunction.
•  Is the second-row seat warmer unit normal?
Yes
Go to the next step.
No
Replace the second-row seat warmer unit which has a malfunction, then go to Step 14.
(See SECOND-ROW SEAT REMOVAL/INSTALLATION.)
12
DETERMINE IF MALFUNCTION CAUSE IS REAR CLIMATE CONTROL UNIT
•  Inspect the rear climate control unit.
•  Is the rear climate control unit normal?
Yes
Go to the next step.
No
Replace the rear climate control unit, then go to Step 14.
(See REAR CLIMATE CONTROL UNIT REMOVAL/INSTALLATION.)
13
DETERMINE IF MALFUNCTION CAUSE IS SECOND-ROW SEAT WARMER CONTROL UNIT
•  Reconnect all the disconnected connectors.
•  Connect the negative battery terminal.
•  Switch the ignition ON (engine off or on).
•  Operate the second-row seat warmer switch to turn on the second-row seat warmer system.
•  Does the second-row seat warmer system operate normally?
Yes
Go to the next step.
No
Replace the second-row seat warmer control unit, then go to the next step.
(See SECOND-ROW SEAT WARMER CONTROL UNIT REMOVAL/INSTALLATION.)
14
VERIFY IF MALFUNCTION CAUSE IS CORRECTED
•  Operate the second-row seat warmer switch to turn on the second-row seat warmer system.
•  Does the second-row seat warmer system operate normally?
Yes
Troubleshooting completed. (Explain the contents of the servicing to the customer.)
No
Verify the malfunction symptom in the symptom troubleshooting chart and perform the other applicable malfunction diagnosis.
(See SYMPTOM TROUBLESHOOTING [SEAT WARMER SYSTEM].)


Captain seat type (with seat ventilation system)

Description
The seat warmer does not warm up even if the seat warmer switch is turned on.
Possible Causes
•  Second-row seat warmer switch malfunction
•  Second-row seat warmer control unit power supply circuit malfunction
―  Short to ground in wiring harness between the following terminals:
•  R.SEAT W 20 A fuse and second-row seat warmer control unit terminal C
•  R.SEAT W 20 A fuse and second-row seat warmer control unit terminal D
•  C/U IG1 15 A fuse and second-row seat warmer control unit terminal H
―  R.SEAT W 20 A fuse malfunction
―  C/U IG1 15 A fuse malfunction
―  Open circuit in wiring harness between the following terminals:
•  R.SEAT W 20 A fuse and second-row seat warmer control unit terminal C
•  R.SEAT W 20 A fuse and second-row seat warmer control unit terminal D
•  C/U IG1 15 A fuse and second-row seat warmer control unit terminal H
•  Open circuit in wiring harness between the following terminals:
―  Second-row seat warmer control unit terminal Q and body ground
―  Second-row seat warmer control unit terminal R and body ground
•  Malfunction in wiring harness between second-row seat warmer control unit terminal F and second-row seat warmer switch terminal C
―  Short to ground in wiring harness between second-row seat warmer control unit terminal F and second-row seat warmer switch terminal C
―  Open circuit in wiring harness between second-row seat warmer control unit terminal F and second-row seat warmer switch terminal C
•  Second-row seat warmer switch malfunction
•  Second-row seat warmer unit malfunction
•  Second-row seat warmer control unit malfunction
•  Connector poor contact or terminal damage

Diagnostic Procedure

Step

Inspection

Action
1
DETERMINE MALFUNCTION SYMPTOM
•  Operate the seat warmer switches on the driver and passenger sides to turn on the seat warmer system for the driver and passenger sides.
•  Does a malfunction occur with the seat warmer system on both sides?
Yes
Go to Step 8.
No
Go to the next step.
2
INSPECT FRONT SECOND-ROW SEAT WARMER CONTROL UNIT CONNECTOR AND SEAT WARMER UNIT CONNECTOR
•  Switch the ignition OFF.
•  Disconnect the negative battery terminal.
•  Disconnect the front second-row seat warmer control unit connector and the second-row seat warmer unit connector on the side which does not operate.
•  Inspect the connector engagement and connection condition, and inspect the terminals for damage, deformation, corrosion, or disconnection.
•  Is the connector normal?
Yes
Go to the next step.
No
Repair or replace the connector, then go to Step 11.
3
VERIFY IF MALFUNCTION CAUSE IS SECOND-ROW SEAT WARMER CONTROL UNIT POWER SUPPLY CIRCUIT
•  Verify that the second-row seat warmer control unit connector is disconnected.
•  Connect the negative battery terminal.
•  Switch the ignition ON (engine off or on).
•  Measure the voltage at the following terminals (vehicle wiring harness side):
―  Second-row seat warmer control unit terminal C
―  Second-row seat warmer control unit terminal D
―  Second-row seat warmer control unit terminal H
•  Is the voltage B+?
Yes
Go to the next step.
No
Inspect the R.SEAT W 20 A fuse and C/U IG1 15 A fuse.
If the fuse is blown:
•  Refer to the wiring diagram and verify if there is a common wiring harness between the following terminals.
―  R.SEAT W 20 A fuse and second-row seat warmer control unit terminal C
―  R.SEAT W 20 A fuse and second-row seat warmer control unit terminal D
―  C/U IG1 15 A fuse and second-row seat warmer control unit terminal H
If there is a common connector:
•  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.
•  Repair or replace the malfunctioning location.
If there is no common connector:
•  Repair or replace the wiring harness which is shorted to ground.
•  Replace the fuse.
If the fuse is damaged:
•  Replace the fuse.
If the fuse is normal:
•  Refer to the wiring diagram and verify if there is a common wiring harness between the following terminals.
―  R.SEAT W 20 A fuse and second-row seat warmer control unit terminal C
―  R.SEAT W 20 A fuse and second-row seat warmer control unit terminal D
―  C/U IG1 15 A fuse and second-row seat warmer control unit terminal H
If there is a common connector:
•  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for an open circuit to determine the malfunctioning location.
•  Repair or replace the malfunctioning location.
If there is no common connector:
•  Repair or replace the wiring harness which has an open circuit.
Go to Step 11.
4
VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS BETWEEN SECOND-ROW SEAT WARMER CONTROL UNIT AND BODY GROUND
•  Switch the ignition OFF (LOCK).
•  Disconnect the negative battery terminal.
•  Verify that the second-row seat warmer control unit connector is disconnected.
•  Inspect for continuity between the following terminals (vehicle wiring harness side) and body ground.
―  Second-row seat warmer control unit terminal Q
―  Second-row seat warmer control unit terminal R
•  Is there continuity?
Yes
Go to the next step.
No
•  Refer to the wiring diagram and verify if there is a common connector between the following terminals and body ground.
―  Second-row seat warmer control unit terminal Q
―  Second-row seat warmer control unit terminal R
If there is a common connector:
•  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for an open circuit to determine the malfunctioning location.
•  Repair or replace the malfunctioning location.
If there is no common connector:
•  Repair or replace the wiring harness which has an open circuit.
•  Go to Step 11.
5
VERIFY IF MALFUNCTION CAUSE IS SHORT CIRCUIT TO GROUND IN WIRING HARNESS BETWEEN SECOND-ROW SEAT WARMER CONTROL UNIT AND SECOND-ROW SEAT WARMER SWITCH
•  Verify that the second-row seat warmer control unit connector is disconnected.
•  Disconnect the second-row seat warmer switch connector.
•  Inspect for continuity between second-row seat warmer control unit terminal F (vehicle wiring harness side) and body ground.
•  Is there continuity?
Yes
•  Refer to the wiring diagram and verify if there is a common connector between second-row seat warmer control unit terminal F and second-row seat warmer switch terminal C.
If there is a common connector:
―  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for short to ground to determine the malfunctioning location.
―  Repair or replace the malfunctioning location.
If there is no common connector:
―  Repair or replace the wiring harness which is shorted to ground.
•  Go to Step 11.
No
Go to the next step.
6
VERIFY IF MALFUNCTION CAUSE IS OPEN CIRCUIT IN WIRING HARNESS BETWEEN SECOND-ROW SEAT WARMER CONTROL UNIT AND SECOND-ROW SEAT WARMER SWITCH
•  Verify that the second-row seat warmer control unit connector and the second-row seat warmer switch connector are disconnected.
•  Inspect the wiring harness for continuity between second-row seat warmer control unit terminal F (vehicle wiring harness side) and second-row seat warmer switch terminal C (vehicle wiring harness side).
•  Is there continuity?
Yes
Go to the next step.
No
•  Refer to the wiring diagram and verify if there is a common connector between second-row seat warmer control unit terminal F and second-row seat warmer switch terminal C.
If there is a common connector:
―  Inspect the common connector and terminals for corrosion, damage, or disconnection and the common wiring harnesses for an open circuit to determine the malfunctioning location.
―  Repair or replace the malfunctioning location.
If there is no common connector:
―  Repair or replace the wiring harness which has an open circuit.
•  Go to Step 11.
7
VERIFY IF MALFUNCTION CAUSE IS SEAT WARMER UNIT
•  Inspect the second-row seat warmer unit on the side which has a malfunction.
•  Is the second-row seat warmer unit normal?
Yes
Go to the next step.
No
Replace the second-row seat warmer unit which has a malfunction, then go to Step 11.
(See SECOND-ROW SEAT REMOVAL/INSTALLATION.)
8
DETERMINE IF MALFUNCTION CAUSE IS SECOND-ROW SEAT WARMER SWITCH
•  Inspect the second-row seat warmer switch.
•  Is the second-row seat warmer switch normal?
Yes
Go to the next step.
No
Replace the second-row seat warmer switch, then go to Step 11.
(See SECOND-ROW SEAT WARMER SWITCH REMOVAL/INSTALLATION.)
9
DETERMINE IF MALFUNCTION CAUSE IS SECOND-ROW SEAT WARMER CONTROL UNIT
•  Reconnect all the disconnected connectors.
•  Connect the negative battery terminal.
•  Switch the ignition ON (engine off or on).
•  Operate the second-row seat warmer switch to turn on the second-row seat warmer system.
•  Does the second-row seat warmer system operate normally?
Yes
Go to the next step.
No
Replace the second-row seat warmer control unit, then go to the next step.
(See SECOND-ROW SEAT WARMER CONTROL UNIT REMOVAL/INSTALLATION.)
10
VERIFY IF MALFUNCTION CAUSE IS CORRECTED
•  Operate the second-row seat warmer switch to turn on the second-row seat warmer system.
•  Does the second-row seat warmer system operate normally?
Yes
Troubleshooting completed. (Explain the contents of the servicing to the customer.)
No
Verify the malfunction symptom in the symptom troubleshooting chart and perform the other applicable malfunction diagnosis.
(See SYMPTOM TROUBLESHOOTING [SEAT WARMER SYSTEM].)