Pinpoint Test M: The Heated Seat Is Inoperative/Does Not Operate Correctly - Passenger
Seats
Pinpoint Tests
Pinpoint Test M: The Heated Seat is Inoperative/Does Not Operate Correctly - Passenger
Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information. Diagrams By Number
Normal Operation
The HVAC module contains the passenger heated seat control button and indicator. The heated seat system functions independently from the climate control system. A heated seat relay is located underneath the passenger seat cushion frame. There are 2 voltage supplies to the heated seat relay. Voltage is supplied from the Smart Junction Box (SJB) heated seat relay enable circuit CBP42 (GN) to the passenger heated seat relay coil when the engine is running. Ground is supplied to the opposite side of the passenger relay coil by the HVAC module passenger heated seat relay drive circuit CHS30 (GY/YE) when the passenger heated seat switch button is pressed to energize the relay. This closes the relay contacts to supply battery voltage from the SJB circuit SBP18 (YE/RD) to the passenger heater mat circuit CHS07 (GY/BU). The passenger heater mats are directly connected to ground circuit GD179 (BK/VT) completing the electrical circuit to heat the seat.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Heated seat relay
- Heater mat
- HVAC module
PINPOINT TEST M: THE HEATED SEAT IS INOPERATIVE/DOES NOT OPERATE CORRECTLY - PASSENGER
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M1 CHECK THE PASSENGER HEATED SEAT INDICATOR OPERATION
- Ignition ON.
- Press the passenger heated seat switch to ON.
- Does the passenger heated seat switch indicator illuminate?
Yes
GO to M2.
No
VERIFY the climate control system is operating OK. For any climate control system concerns, REFER to Heating and Air Conditioning. If OK, key OFF and DISASSEMBLE as necessary to disconnect the HVAC module electrical connectors. WAIT one minute to allow the system to reset and RECONNECT the electrical connectors. RETEST the system. If the heated seat indicator still does not illuminate, INSTALL a new HVAC module. TEST the system for normal operation.
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M2 CHECK THE HEATED SEAT RELAY
- Ignition OFF.
- Swap the passenger heated seat relay with the driver heated seat relay.
- Does the seat heat when the heated seat switch is depressed?
Yes
INSTALL a new heated seat relay. TEST the system for normal operation.
No
GO to M3.
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M3 CHECK THE HEATED SEAT RELAY FOR VOLTAGE
- Ignition OFF.
- Disconnect: Passenger Heated Seat Relay C329.
- Ignition ON.
- Measure the voltage between:
- passenger heated seat relay C329-5 circuit SBP18 (YE/RD), harness side and ground.
- passenger heated seat relay C329-2 circuit CBP42 (GN), harness side and ground.
- Are the voltages greater than 10 volts?
Yes
GO to M4.
No
REPAIR the affected circuit SBP18 (YE/RD) or CBP42 (GN). TEST the system for normal operation.
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M4 CHECK FOR AN OPEN GROUND CIRCUIT
- Ignition OFF.
- Disconnect: Passenger Seat Backrest Heater Mat C335.
- Measure the resistance between passenger seat backrest heater mat C335-1 circuit GD179 (BK/VT), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to M5.
No
REPAIR the circuit. TEST the system for normal operation.
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M5 CHECK CIRCUIT CHS07 (GY/BU) FOR AN OPEN
- Measure the resistance between passenger heated seat relay C329-3 circuit CHS07 (GY/BU), harness side and passenger cushion heater mat C334-4 circuit CHS07 (GY/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to M6.
No
REPAIR the circuit. TEST the system for normal operation.
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M6 CHECK THE CUSHION HEATER MAT FOR AN OPEN
- Disconnect: Passenger Cushion Heater Mat C334.
- Measure the resistance between passenger cushion heater mat connector pins 1 and 4, component side.
- Is the resistance between 0.8 and 1.3 ohms?
Yes
GO to M7.
No
INSTALL a new backrest heater mat. TEST the system for normal operation.
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M7 CHECK CIRCUIT CHS06 (BU/BN) FOR AN OPEN
- Measure the resistance between passenger cushion heater mat C334-1 circuit CHS06 (BU/BN), harness side and passenger backrest heater mat C335-2 circuit CHS06 (BU/BN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to M8.
No
REPAIR the circuit. TEST the system for normal operation.
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M8 CHECK THE BACKREST HEATER MAT FOR AN OPEN
- Measure the resistance between passenger backrest heater mat connector pins 1 and 2, component side.
- Is the resistance between 0.8 and 1.3 ohms?
Yes
GO to M9.
No
INSTALL a new backrest heater mat. TEST the system for normal operation.
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M9 CHECK CIRCUIT CHS30 (GY/YE) FOR AN OPEN
- Disconnect: HVAC Module C228B or C2357A.
- Vehicles with HVAC C228B, measure the resistance between passenger heated seat relay C329-1 circuit CHS30 (GY/YE), harness side and HVAC C228B-3 circuit CHS30 (GY/YE), harness side.
- Vehicles with HVAC C2357A, measure the resistance between passenger heated seat relay C329-1 circuit CHS30 (GY/YE), harness side and HVAC C2357A-5 circuit CHS30 (GY/YE), harness side.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new HVAC module.
No
REPAIR the circuit. TEST the system for normal operation.
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