Pinpoint Test L: The Heated Seat is Inoperative/Does Not Operate Correctly - Driver
Seats
Pinpoint Tests
Pinpoint Test L: The Heated Seat is Inoperative/Does Not Operate Correctly - Driver
Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information. Diagrams By Number
Normal Operation
The HVAC module contains the driver 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 driver 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 driver heated seat relay coil when the ignition is ON. Ground is supplied to the opposite side of the driver relay coil by the HVAC module driver heated seat relay drive circuit CHS29 (WH/BU) when the driver 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 driver heater mat circuit CHS02 (YE/BU). The driver 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 L: THE HEATED SEAT IS INOPERATIVE/DOES NOT OPERATE CORRECTLY - DRIVER
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L1 CHECK THE DRIVER HEATED SEAT INDICATOR OPERATION
- Ignition ON.
- Press the driver heated seat switch to ON.
- Does the driver heated seat switch indicator illuminate?
Yes
GO to L2.
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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L2 CHECK THE HEATED SEAT RELAY
- Ignition OFF.
- Swap the driver heated seat relay with the passenger 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 L3.
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L3 CHECK THE HEATED SEAT RELAY FOR VOLTAGE
- Ignition OFF.
- Disconnect: Driver Heated Seat Relay C359.
- Ignition ON.
- Measure the voltage between:
- driver heated seat relay C359-5 circuit SBP18 (YE/RD), harness side and ground.
- driver heated seat relay C359-2 circuit CBP42 (GN), harness side and ground.
- Are the voltages greater than 10 volts?
Yes
GO to L4.
No
REPAIR the affected circuit SBP18 (YE/RD) or CBP42 (GN). TEST the system for normal operation.
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L4 CHECK FOR AN OPEN GROUND CIRCUIT
- Ignition OFF.
- Disconnect: Driver Seat Backrest Heater Mat C365.
- Measure the resistance between driver seat backrest heater mat C365-1 circuit GD179 (BK/VT), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to L5.
No
REPAIR the circuit. TEST the system for normal operation.
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L5 CHECK CIRCUIT CHS02 (YE/BU) FOR AN OPEN
- Measure the resistance between driver heated seat relay C359-3 circuit CHS02 (YE/BU), harness side and driver cushion heater mat C364-4 circuit CHS02 (YE/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to L6.
No
REPAIR the circuit. TEST the system for normal operation.
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L6 CHECK THE CUSHION HEATER MAT FOR AN OPEN
- Disconnect: Driver Cushion Heater Mat C364.
- Measure the resistance between driver cushion heater mat pins 1 and 4, component side.
- Is the resistance between 0.8 and 1.3 ohms?
Yes
GO to L7.
No
INSTALL a new seat cushion heater mat. TEST the system for normal operation.
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L7 CHECK CIRCUIT CHS01 (GY/VT) FOR AN OPEN
- Measure the resistance between driver cushion heater mat C364-1 circuit CHS01 (GY/VT), harness side and driver backrest heater mat C365-2 circuit CHS01 (GY/VT), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to L8.
No
REPAIR the circuit. TEST the system for normal operation.
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L8 CHECK THE BACKREST HEATER MAT FOR AN OPEN
- Measure the resistance between driver backrest heater mat connector pins 1 and 2, component side.
- Is the resistance between 0.8 and 1.3 ohms?
Yes
GO to L9.
No
INSTALL a new backrest heater mat. TEST the system for normal operation.
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L9 CHECK CIRCUIT CHS29 (WH/BU) FOR AN OPEN
- Disconnect: HVAC Module C228B or C2357A.
- Vehicles with HVAC C228B, measure the resistance between driver heated seat relay C359-1 circuit CHS29 (WH/BU), harness side and HVAC C228B-6 circuit CHS29 (WH/BU), harness side.
- Vehicles with HVAC C2357A, measure the resistance between driver heated seat relay C359-1 circuit CHS29 (WH/BU), harness side and HVAC C2357A-1 circuit CHS29 (WH/BU), 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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