Pinpoint Test C: The Heated Seat Is Inoperative/Does Not Operate Correctly - Passenger
Seats
Pinpoint Tests
Pinpoint Test C: The Heated Seat is Inoperative/Does Not Operate Correctly - Passenger
Refer to Wiring Diagrams Set 119, Climate Controlled Seats for schematic and connector information. Diagrams By Number
Normal Operation
There are 2 voltage supplies to the heated seat relay. When the ignition switch is ON, voltage is supplied from the Smart Junction Box (SJB) to the heated seat relay coil through heated seat relay enable circuit CHS25 (YE). When the engine is running and the heated seat switch button is pressed on, ground is supplied to the opposite side of the relay coil by HVAC module passenger heated seat relay drive circuit CHS30 (GY/YE) to energize the relay. The switch indicator can only be illuminated with the engine running. The relay contact closes to supply battery voltage from circuit CHS02 (YE/BU) to the passenger heater mat circuit CHS07 (GY/BU). The passenger heater mats are connected to ground circuit GD905 (BK/BN) completing the electrical circuit to heat the seat.
- DTC B12AD Passenger Heated Seat Relay Drive Circuit Shorted to Battery Voltage - If the passenger heated seat relay drive circuit CHS07 (GY/BU) is shorted to voltage and the HVAC module attempts to activate the passenger heated seat relay, the DTC will set and the seat will fail to heat.
- DTC B12AE Passenger Heated Seat Relay Drive Circuit Open or Shorted to Ground - If the passenger heated seat relay drive circuit CHS07 (GY/BU) is open or shorted to ground and the HVAC module attempts to activate the passenger heated seat relay, the DTC will set and the seat will fail to heat (circuit open) or may be on at all times (circuit shorted to ground) until the ignition key is OFF.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Heated seat relay
- Backrest or cushion heater mat
- HVAC module
PINPOINT TEST C: THE HEATED SEAT IS INOPERATIVE/DOES NOT OPERATE CORRECTLY - PASSENGER
NOTE: Several heated seat circuits change circuit numbers and wire colors at the seat-to-body electrical connectors. Be sure circuits are tested as described in this procedure for correct diagnosis. Refer to Wiring Diagrams Set 119, Climate Controlled Seats for schematic and connector information. Diagrams By Number
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C1 CHECK THE HEATED SEAT AND INDICATOR OPERATION
- Start the engine.
- Operate the system, check the heated seat indicator for illumination and determine if the seat is heating.
- Does the heated seat indicator illuminate and does the seat heat?
Yes
Key OFF. GO to C11 to check the heater mats for an intermittent open circuit.
No
GO to C2.
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C2 CHECK THE HVAC SYSTEM OPERATION AND HVAC MODULE FOR DTCs
- Verify the HVAC system operates.
- Enter the following diagnostic mode on the scan tool: Self Test - HVAC Module.
- Is DTC B12AD or B12AE retrieved?
Yes
If DTC B12AD is present, GO to C3.
If DTC B12AE is present, GO to C4.
For any other HVAC module DTC or HVAC system concerns, REFER to Heating and Air Conditioning for diagnosis.
No
GO to C6.
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C3 CHECK THE CONTROL CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Depower the Supplemental Restraint System (SRS). Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Air Bag Systems.
- Disconnect: Passenger Seat Side Air Bag C337.
- Disconnect: Passenger Safety Belt Buckle and Pretensioner C3202.
- Disconnect: Passenger Heated Seat Relay C3261.
- Disconnect: HVAC Module C2357a.
- WARNING: Make sure no one is in the vehicle and there is nothing blocking or placed in front of any air bag module when the battery is connected. Failure to follow these instructions may result in serious personal injury in the event of an accidental deployment.
- Connect the battery ground cable. Refer to Battery.
- Ignition ON.
- Measure the voltage between passenger heated seat relay C3261-1, circuit CHS30 (GY/YE), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle and pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
No
INSTALL a new passenger heated seat relay. RECONNECT all connectors and REPEAT the self-test. If the DTC is retrieved again, INSTALL a new HVAC module.
CLEAR the DTCs. REPEAT the self-test.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle and pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
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C4 CHECK THE CONTROL CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Air Bag Systems.
- Disconnect: Passenger Seat Side Air Bag C337.
- Disconnect: Passenger Safety Belt Buckle and Pretensioner C3202.
- Disconnect: Passenger Heated Seat Relay C3261.
- Disconnect: HVAC Module C2357a.
- Measure the resistance between passenger heated seat relay C3261-1, circuit CHS30 (GY/YE), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to C5.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
CONNECT passenger seat safety belt buckle and pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
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C5 CHECK THE CONTROL CIRCUIT FOR AN OPEN
- Measure the resistance between passenger heated seat relay C3261-1, circuit CHS30 (GY/YE), harness side and HVAC module C2357a-5, circuit CHS07 (GY/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
CHECK the relay and HVAC module connectors and pins for damage. REPAIR as necessary. RECONNECT the connectors. REPEAT the self-test. If the DTC is retrieved again, INSTALL a new HVAC module. CLEAR the DTCs. REPEAT the self-test.
CONNECT passenger seat safety belt buckle and pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
CONNECT passenger seat safety belt buckle and pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
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C6 CHECK THE HEATER CIRCUIT FOR VOLTAGE
- Ignition OFF.
- Depower the SRS. Refer to Supplemental Restraint System (SRS) Depowering and Repowering in the General Procedures portion of Air Bag Systems.
- Disconnect: Passenger Seat Side Air Bag C337.
- Disconnect: Passenger Safety Belt Buckle and Pretensioner C3202.
- Disconnect: Passenger Cushion Heater Mat C334.
- WARNING: Make sure no one is in the vehicle and there is nothing blocking or placed in front of any air bag module when the battery is connected. Failure to follow these instructions may result in serious personal injury in the event of an accidental deployment.
- Connect the battery ground cable. Refer to Battery.
- Start the engine.
- Press the passenger heated seat switch on and measure the voltage between passenger seat heater mat C334-1, circuit CHS07 (GY/BU), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to C10.
No
GO to C7.
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C7 SWAP HEATED SEAT RELAYS AND CHECK THE HEATER CIRCUIT FOR VOLTAGE
- Ignition OFF.
- Disconnect: Passenger Heated Seat Relay C3261.
- Disconnect: Driver Heated Seat Relay C3260.
- Swap relays by installing the driver heated seat relay into the passenger heated seat relay connector.
- Start the engine.
- Press the passenger heated seat switch on and measure the voltage between passenger seat heater mat C334-1, circuit CHS07 (GY/BU), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new heated seat relay. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle and pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
No
DISCONNECT the test relay and GO to C8.
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C8 CHECK FOR VOLTAGE TO THE PASSENGER HEATED SEAT RELAY
- Measure the voltage between:
- passenger heated seat relay C3261-3, circuit CHS02 (YE/BU), harness side and ground.
- passenger heated seat relay C3261-2, circuit CHS25 (YE), harness side and ground.
- Are the voltages greater than 10 volts?
Yes
GO to C9.
No
VERIFY SJB fuses 18 (20A) and 43 (10A) are OK. If OK, REPAIR the circuit(s). If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle and pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
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C9 CHECK THE HEATER CIRCUIT FOR AN OPEN
- Ignition OFF.
- Measure the resistance between passenger heated seat relay C3261-5, circuit CHS07 (GY/BU), harness side and passenger cushion heater mat C334-1, circuit CHS07 (GY/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new HVAC module. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle and pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle and pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
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C10 CHECK THE HEATER MAT GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Measure the resistance between passenger seat heater mat C334-2, circuit GD905 (BK/GN), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to C11.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle and pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
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C11 CHECK RESISTANCE OF THE CUSHION AND BACKREST HEATER MATS AND FOR AN INTERMITTENT OPEN
NOTE: Heater mat resistance tolerances are tight. Resistance can vary with temperature. Measurements should be carried out with the seat at room temperature.
- Disconnect: Passenger Cushion Heater Mat C334.
- Carry out the following measurements with an occupant in the seat and check for an open heater mat with weight on the seat.
- Measure the resistance between passenger cushion heater mat C334 pins 1 and 2, component side (measures both cushion and backrest heater mats together in series).
- Disconnect: Passenger Backrest Heater Mat Electrical Connector.
- Measure the resistance between passenger backrest heater mat electrical connector pins 1 and 2, component side (measures backrest heater mat only).
- Is the resistance between 2.5 and 5 ohms at the cushion heater mat and between 1.0 and 2.5 ohms at the backrest heater mat with the seat occupied?
Yes
The system checks OK at this time. CHECK for loose or damaged connector pins and wiring damage. REPAIR as needed. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle and pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
No
If resistance of the backrest heater mat is OK, INSTALL a new cushion heater mat. REFER to Seat Cushion Heater Mat Seat Cushion Heater Mat. Otherwise, INSTALL a new backrest heater mat. REFER to Seat Backrest Heater Mat Seat Backrest Heater Mat. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.
DISCONNECT the battery ground cable. CONNECT passenger seat safety belt buckle and pretensioner C3202 and passenger seat side air bag C337.
REPOWER the SRS. REFER to Air Bag Systems.
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