Pinpoint Test Q: The Heated Seats are Inoperative - Rear
Seats
Pinpoint Tests
Pinpoint Test Q: The Heated Seats are Inoperative - Rear
Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information. Diagrams By Number
Normal Operation
When the LH or RH rear heated seat control switch is activated with the ignition ON, a ground signal is supplied to the heated seat module to command the system in high heat mode or low heat mode. When commanded ON, voltage is supplied to the heated seat switch from the heated seat module to illuminate the switch indicator. The heated seat module also supplies voltage to the LH or RH rear seat cushion and backrest heater mats, which are connected in series. Temperature is maintained by the heated seat module using a sensor contained within the cushion heater mat. The heated seat module supplies a reference voltage to the temperature sensor and monitors the return signal from the temperature sensor for controlling current flow to the heater mats. The heated seat module remains ON, heating the seat and maintaining temperature until switched OFF or the ignition voltage is switched OFF.
A new heated seat module must be configured after installation for correct operation. To configure, press the low heat mode button on either rear heated seat switch. Module configuration will occur automatically after the low heat mode button is pressed. Until the module is correctly configured, the heated seats will operate incorrectly when selecting the high heat mode by following a sequence of high, low and off with each button press. The system will operate correctly after the heated seat module receives a low heat request on either of the low heat request circuits and rear heated seat module configuration is activated.
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- Heated seat module
PINPOINT TEST Q: THE HEATED SEATS ARE INOPERATIVE - REAR
NOTICE: Use the correct probe adapter(s) from the Flex Probe Kit when taking measurements. Failure to use the correct probe adapter(s) may damage the connector.
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Q1 CHECK FOR VOLTAGE TO THE HEATED SEAT MODULE
- For electrical connector access, release and lower the rear 60 percent seat backrest. Refer to the appropriate steps in Heated Seat Module - Rear Heated Seat Module - Rear.
- Disconnect: Heated Seat Module C3162B.
- Ignition ON.
- Measure the voltage between:
- rear heated seat module C3162B-2, circuit CBP33 (WH/BN), harness side and ground.
- rear heated seat module C3162B-1, circuit SBB71 (WH/RD), harness side and ground.
- Are the voltages greater than 10 volts?
Yes
GO to Q2.
No
VERIFY Battery Junction Box (BJB) fuse 71 (20A) and Body Control Module (BCM) fuse 33 (10A) are OK. If OK, REPAIR the circuit(s). If not OK, REFER to the Wiring Diagrams to identify possible causes of the circuit short. TEST the system for normal operation. Diagrams By Number
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Q2 CHECK THE REAR HEATED SEAT MODULE GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Measure the resistance between rear heated seat module C3162B-5, circuit GD134 (BK/VT), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to Q3.
No
REPAIR the circuit. TEST the system for normal operation.
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Q3 CHECK THE REAR HEATED SEAT SWITCH GROUND CIRCUIT FOR AN OPEN
- Disconnect: Heated Seat Module C3162A.
- NOTE: This step will verify if the shared ground supplied to both heated seat switches is open by measuring the switch input resistance at the heated seat module.
- Measure the resistance between rear heated seat module C3162A-2, circuit CHS46 (YE/GN), harness side and ground while pressing the LH heated seat switch to high.
- Is the resistance less than 30 ohms when the switch is pressed and greater than 10,000 ohms when not pressed?
Yes
GO to Q4.
No
REPAIR circuit GD139 (BK/YE). TEST the system for normal operation.
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Q4 CHECK THE TEMPERATURE SENSOR RETURN CIRCUIT FOR AN OPEN
- Measure the resistance between heated seat module C3162A-12, circuit RHS41 (GN/BN), harness side and C3162A-3, circuit VHS42 (GN), harness side.
- Is the resistance between 300 and 300K ohms?
Yes
INSTALL a new heated seat module. REFER to Heated Seat Module - Rear Heated Seat Module - Rear. TEST the system for normal operation.
No
REPAIR circuit RHS41 (GN/BN). TEST the system for normal operation.
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