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
Battery voltage is supplied to the heated seat module on circuit SBP40 (VT/RD) and ground on circuit GD134 (BK/VT). With the ignition ON, voltage is also supplied to the heated seat module on circuit CBP35 (YE/BU). The heated seat switches share ground circuit GD139 (BK/YE) and supply a momentary ground signal to the heated seat module when pressed on and off. The heated seat module supplies voltage to the heater mats to heat the seats and monitors temperature sensors in the cushion heater mats to regulate seat temperature. The temperature sensors share return circuit RHS41 (GN/BN) to the heated seat module and if open will cause both seats to be inoperative. The heated seat module is designed to remain on and maintain seat temperature until switched off or ignition is 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 CBP35 (YE/BU), harness side and ground.
- rear heated seat module C3162B-1, circuit SBP40 (VT/RD), harness side and ground.
- Are the voltages greater than 10 volts?
Yes
GO to Q2.
No
VERIFY Smart Junction Box (SJB) fuses 40 (20A) and 35 (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. Diagrams By Number
TEST the system for normal operation.
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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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