Pinpoint Test M: The Heated Seat is Inoperative/Does Not Operate Correctly - Left Rear
Seats
Pinpoint Test M: The Heated Seat is Inoperative/Does Not Operate Correctly - Left Rear
Normal Operation
The heated seat module receives constant battery voltage on circuit SBB07 (WH/RD). When ignition voltage is supplied and the LH heated seat button on the Rear Heating Ventilation Air Conditioning (RHVAC) module is pressed, a momentary ground signal is sent to the heated seat module on command circuit CHS47 (VT/GN) to turn the system on or off. Upon receiving a signal, the heated seat module will decrease one setting (the sequence is high, low, off, high). The heated seat module supplies voltage to the cushion and backrest heater mats. The cushion and backrest heater mats are connected in series and operate together. Temperature is maintained by a temperature sensor contained within the cushion heater mat. The heated seat module supplies a reference voltage to the temperature sensor and monitors the signal to control current flow to the heater mats.
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- Backrest or cushion heater mat
- RHVAC (Rear Heating Ventilation Air Conditioning) module
- Rear heated seat module
PINPOINT TEST M : THE HEATED SEAT IS INOPERATIVE/DOES NOT OPERATE CORRECTLY - LEFT REAR
M1 CHECK THE DTCs FROM THE SELF-TEST
- Connect the scan tool.
- Ignition ON.
- Retrieve the RHVAC (Rear Heating Ventilation Air Conditioning) module DTCs.
Are any DTCs present?
Yes
For DTC B1031:11, GO to M14.
For DTC B1031:12, GO to M13.
For DTC B1031:13, GO to M15.
For all other DTCs, REFER to Heating and Air Conditioning.
No
GO to M2.
M2 CHECK VOLTAGE TO THE REAR HEATED SEAT MODULE
- Disconnect: Heated Seat Module C3304B.
- Measure the voltage between:
- heated seat module C3304B-1, circuit SBB07 (WH/RD), harness side and ground.
Is the voltage greater than 10 volts?
Yes
GO to M3.
No
REPAIR the circuit. TEST the system for normal operation.
M3 CHECK THE HEATED SEAT MODULE GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Measure the resistance between heated seat module C359B-5, circuit GD145 (BK/BU), harness side and ground.
Is the resistance less than 5 ohms?
Yes
GO to M4.
No
REPAIR the circuit. TEST the system for normal operation.
M4 CHECK LEFT REAR HEATER MATS RESISTANCE AND HEATER CIRCUITS FOR AN OPEN
- Measure the resistance between rear heated seat module C3304B-4, circuit CHS39 (GN/BU), harness side and ground.
Is the resistance between 1.2 and 4 ohms?
Yes
GO to M9.
No
GO to M5.
M5 CHECK LEFT REAR SEAT CUSHION HEATER CIRCUIT FOR AN OPEN AND SHORT TO GROUND
- Disconnect: LH Cushion Heater Mat C3167.
- Measure the resistance between:
- heated seat module C3304B-4, circuit CHS39 (GN/BU), harness side and driver seat cushion heater mat C3167-1, circuit CHS39 (GN/BU), harness side.
- heated seat module C3304B-4, circuit CHS39 (GN/BU), harness side and ground.
Is the resistance less than 5 ohms between heated seat module and cushion heater mat and greater than 10,000 ohms between the heated seat module and ground?
Yes
GO to M6.
No
REPAIR the circuit. TEST the system for normal operation.
M6 CHECK LEFT REAR HEATER MATS GROUND CIRCUIT FOR AN OPEN
- Disconnect: LH Backrest Heater Mat C3168.
- Measure the resistance between left rear backrest heater mat C3168-1, circuit GD133 (BK), harness side and ground.
Is the resistance less than 5 ohms?
Yes
GO to M7.
No
REPAIR the circuit. TEST the system for normal operation.
M7 CHECK LEFT REAR CUSHION HEATER MAT FOR AN OPEN
- Measure the resistance between left rear cushion heater mat C3167 pins 1 and 4, component side.
Is the resistance between 0.6 and 2 ohms?
Yes
GO to M8.
No
INSTALL a new rear cushion heater mat. REFER to Seat Cushion Heater Mat - Second Row, 60 Percent . TEST the system for normal operation.
M8 CHECK LEFT REAR BACKREST HEATER MAT FOR AN OPEN
- Measure the resistance between left rear backrest heater C3168 pins 1 and 2, component side.
Is the resistance between 0.6 and 2 ohms?
Yes
REPAIR circuit CHS40 (GY/VT). TEST the system for normal operation.
No
INSTALL a new rear backrest heater mat. REFER to Seat Backrest Heater Mat - Second Row, 60 Percent . TEST the system for normal operation.
M9 CHECK TEMPERATURE SENSOR CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: Heated Seat Module C3304A.
- Ignition ON.
- Measure the voltage between rear heated seat module C3304A-3, circuit VHS42 (GN), harness side and ground.
Is any voltage present?
Yes
REPAIR the circuit.
GO to M11 to check the temperature sensor.
TEST the system for normal operation.
No
GO to M10.
M10 CHECK HEATED SEAT TEMPERATURE SENSOR CIRCUITS FOR AN OPEN AND SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between:
- rear heated seat module C3304A-3, circuit VHS42 (GN), harness side and C3304A-12, circuit RHS41 (GN/BN), harness side.
- rear heated seat module C3304A-3, circuit VHS42 (GN), harness side and ground.
Is the resistance greater than 300 and less than 300,000 ohms between C3304A-3 and C3304A-12 and greater than 10,000 ohms between C3304A-3 and ground?
Yes
GO to M16.
No
GO to M11.
M11 CHECK HEATED SEAT TEMPERATURE SENSOR CIRCUIT FOR AN OPEN AND SHORT TO GROUND
- Disconnect: LH Cushion Heater Mat C3167.
- Measure the resistance between:
- rear heated seat module C3304A-3, circuit VHS42 (GN), harness side and rear seat cushion heater mat C3167-2, circuit VHS42 (GN), harness side.
- rear heated seat module C3304A-3, circuit VHS42 (GN), harness side and ground.
Is the resistance less than 5 ohms between C3304A-3 and C3167-2, and greater than 10,000 ohms between C3304A-3 and ground?
Yes
GO to M12.
No
REPAIR the circuit. TEST the system for normal operation.
M12 CHECK TEMPERATURE SENSOR FOR AN OPEN
- Measure the resistance between rear heated seat cushion C3167 pin 2 and pin 3, component side.
Is the resistance between 300 ohms and 300,000 ohms?
Yes
REPAIR circuit RHS41 (GN/BN). TEST the system for normal operation.
No
INSTALL a new rear seat cushion heater mat. REFER to Seat Cushion Heater Mat - Second Row, 60 Percent . TEST the system for normal operation.
M13 CHECK HEATED SEAT MODULE COMMAND CIRCUIT FOR SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: RHVAC (Rear Heating Ventilation Air Conditioning) C3198.
- Disconnect: Heated Seat Module C3304A.
- Ignition ON.
- Measure the voltage between heated seat module C3304A-2, circuit CHS47 (VT/GN), harness side and ground.
Is any voltage present?
Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
No
GO to M16.
M14 CHECK HEATED SEAT MODULE COMMAND CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: RHVAC (Rear Heating Ventilation Air Conditioning) C3198.
- Disconnect: Heated Seat Module C3304A.
- Measure the resistance between heated seat module C3304A-2, circuit CHS47 (VT/GN), harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to M16.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
M15 CHECK HEATED SEAT MODULE COMMAND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: RHVAC (Rear Heating Ventilation Air Conditioning) C3198.
- Disconnect: Heated Seat Module C3304A.
- Measure the resistance between heated seat module C3304A-2, circuit CHS47 (VT/GN), harness side and RHVAC (Rear Heating Ventilation Air Conditioning) module C3198-9, circuit CHS47 (VT/GN), harness side.
Is the resistance less than 5 ohms?
Yes
GO to M16.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
M16 CHECK THE RHVAC (Rear Heating Ventilation Air Conditioning) MODULE OUTPUT
- Ignition OFF.
- Connect: RHVAC (Rear Heating Ventilation Air Conditioning) Module C3198.
- Connect: Heated Seat Module C3304A.
- Connect: Heated Seat Module C3304B.
- Start the engine.
- NOTE: The following measurement must be taken by back-probing the heated seat module C3304A.
NOTE: The voltage on circuit CHS47 (VT/GN) should drop momentarily when the driver heated seat control button is pressed.
Measure the voltage between heated seat module C3304A-2, circuit CHS47 (VT/GN), harness side and ground by back-probing heated seat module C3304A-2. Press the driver heated seat control button on the RHVAC (Rear Heating Ventilation Air Conditioning) module and note the voltage.
Is the voltage greater than 10 volts before pressing the driver heated seat control button, then momentarily drops when the heated seat control button is pressed?
Yes
INSTALL a new heated seat module. REFER to Heated Seat Module - Second Row . TEST the system for normal operation.
No
If the voltage is greater than 10 volts but did not drop when the driver heated seat button was pressed, INSTALL a new RHVAC (Rear Heating Ventilation Air Conditioning) module. REFER to Heating and Air Conditioning.
If the voltage is less than 10 volts, INSTALL a new heated seat module. REFER to Heated Seat Module - Second Row .
TEST the system for normal operation.