Pinpoint Test O: The Heated Seat is Inoperative - Left Rear
Seats
Pinpoint Test O: The Heated Seat is Inoperative - Left Rear
Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information. Diagrams By Number
Normal Operation
The left rear heated seat module receives voltage feed on circuit 1445 (RD/LG), ignition voltage feed on circuit 1040 (RD/BK) and is supplied ground on circuit 57 (BK). When the heated seat control switch is pressed with the ignition switch in RUN or START, a ground signal is sent to the heated seat module on circuit 1020 (DG/VT) to command the system ON or OFF in HI heat mode or circuit 1255 (WH/RD) to command the system ON or OFF in LOW heat mode. When commanded ON, a ground signal is supplied to the heated seat switch from the heated seat module on either circuit 1019 (TN/LB) (HI heat mode) or circuit 1018 (LG/OG) illuminating the switch indicator. The heated seat module also supplies voltage to the cushion and backrest heater mats on circuit 1064 (YE/LB) and ground to the heater mats on circuit 1065 (WH/LB). The cushion and backrest heater mats are connected in series and operate together. 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 on circuit 1060 (BK/LB) and monitors the return signal from the temperature sensor on circuit 1061 (BN/LB) for adjusting the current flow to the heater mats. The heated seat module is designed to remain ON, heating the seat and maintaining temperature until switched OFF or the time-out period occurs.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Heater mat
- Heated seat switch
- Heated seat module
PINPOINT TEST O: THE HEATED SEAT IS INOPERATIVE - LEFT REAR
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O1 CHECK THE HEATED SEAT SWITCH INPUT RESISTANCE TO THE HEATED SEAT MODULE
- Ignition OFF.
- Disconnect: Left Rear Heated Seat Module C3162.
- Measure the resistance between:
- left rear heated seat module C3162-8, circuit 1020 (DG/VT), harness side and ground while pressing the heated seat switch.
- left rear heated seat module C3162-11, circuit 1255 (WH/RD), harness side and ground while pressing the heated seat switch.
- Are the resistances less than 75 ohms when the heated seat switch is pressed and greater than 10,000 ohms when the heated seat switch is not pressed?
Yes
GO to O3.
No
GO to O2.
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O2 CHECK HEATED SEAT SWITCH GROUND CIRCUIT 57 (BK)
- Disconnect: Left Rear Heated Seat Switch C722.
- Measure the resistance between left rear heated seat switch C722-1, circuit 57 (BK), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new heated seat switch. TEST the system for normal operation.
No
REPAIR the circuit. TEST the system for normal operation.
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O3 CHECK FOR VOLTAGE TO THE HEATED SEAT MODULE
- Measure the voltage between left rear heated seat module C3162-12, circuit 1445 (RD/LG), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to O4.
No
VERIFY Battery Junction Box (BJB) fuse 2 (20A) is OK. If OK, REPAIR circuit 1445 (RD/LG). If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. TEST the system for normal operation. Diagrams By Number
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O4 CHECK FOR VOLTAGE TO THE HEATED SEAT MODULE
- Ignition ON.
- Measure the voltage between left rear heated seat module C3162-5, circuit 1040 (RD/BK), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to O5.
No
VERIFY Central Junction Box (CJB) fuse 17 (10A) is OK. If OK, REPAIR the circuit. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. TEST the system for normal operation. Diagrams By Number
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O5 CHECK HEATED SEAT MODULE GROUND CIRCUIT 57 (BK)
- Ignition OFF.
- Measure the resistance between left rear heated seat module C3162-1, circuit 57 (BK), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to O6.
No
REPAIR the circuit. TEST the system for normal operation.
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O6 CHECK THE SEAT CUSHION BACKREST HEATER RESISTANCE AND FOR A SHORT TO GROUND
- Measure the resistance between:
- left rear heated seat module C3162-6, circuit 1064 (YE/LB) harness side and C3162-7, circuit 1065 (WH/LB), harness side.
- left rear heated seat module C3162-6, circuit 1064 (YE/LB), harness side and ground.
- Is the resistance greater than 1.6 ohms and less than 10 ohms between heated seat module pins 6 and 7 and greater than 10,000 ohms between heated seat module and ground?
Yes
GO to O7.
No
GO to O13.
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O7 CHECK THE SEAT CUSHION AND BACKREST HEATER CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition ON.
- Measure the voltage between:
- left rear heated seat module C3162-6, circuit 1064 (YE/LB), harness side and ground.
- left rear heated seat module C3162-7, circuit 1065 (WH/LB), harness side and ground.
- Is voltage present on either circuit?
Yes
GO to O8.
No
GO to O9.
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O8 CHECK CIRCUITS 1064 (YE/LB) AND 1065 (WH/LB) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Left Rear Seat Backrest Heater C3168.
- Ignition ON.
- Measure the voltage between:
- left rear heated seat module C3162-6, circuit 1064 (YE/LB), harness side and ground.
- left rear heated seat module C3162-7, circuit 1065 (WH/LB), harness side and ground.
- Is voltage present on either circuit?
Yes
REPAIR the circuit(s). TEST the system for normal operation.
No
REPAIR circuit 1064 (YE/LB) between the left rear seat cushion heater C3167 and the left rear seat backrest heater C3168. TEST the system for normal operation.
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O9 CHECK THE HEATED SEAT TEMPERATURE SENSOR CIRCUITS FOR A SHORT TO VOLTAGE
- Measure the voltage between:
- left rear heated seat module C3162-3, circuit 1061 (BN/LB), harness side and ground.
- left rear heated seat module C3162-4, circuit 1060 (BK/LB), harness side and ground.
- Is voltage present on either circuit?
Yes
REPAIR the circuit(s). TEST the system for normal operation.
No
GO to O10.
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O10 CHECK RESISTANCE OF THE HEATED SEAT TEMPERATURE SENSOR CIRCUITS
- Ignition OFF.
- Measure the resistance between:
- left rear heated seat module C3162-3, circuit 1061 (BN/LB), harness side and C3162-4, circuit 1060 (BK/LB), harness side.
- left rear heated seat module C3162-3, circuit 1061 (BN/LB), harness side and ground.
- Is the resistance between 50 ohms and 300,000 ohms between heated seat module pins 3 and 4 and greater than 10,000 ohms between heated seat module and ground?
Yes
INSTALL a new left rear heated seat module. REFER to Heated Seat Module - Rear Seat Heated Seat Module - Rear Seat. TEST the system for normal operation.
No
GO to O11.
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O11 CHECK CIRCUIT 1061 (BN/LB) FOR AN OPEN OR SHORT TO GROUND
- Disconnect: Left Rear Seat Cushion Heater C3167.
- Measure the resistance between:
- left rear heated seat module C3162-3, circuit 1061 (BN/LB), harness side and left rear seat cushion heater C3167-3, circuit 1061 (BN/LB), harness side.
- left rear heated seat module C3162-3, circuit 1061 (BN/LB), harness side and ground.
- Is the resistance less than 5 ohms between the heated seat module and seat cushion heater and greater than 10,000 ohms between heated seat module and ground?
Yes
GO to O12.
No
REPAIR the circuit. TEST the system for normal operation.
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O12 CHECK CIRCUIT 1060 (BK/LB) FOR AN OPEN OR SHORT TO GROUND
- Measure the resistance between:
- left rear heated seat module C3162-4, circuit 1060 (BK/LB), harness side and left rear seat cushion heater C3167-2, circuit 1060 (BK/LB), harness side.
- left rear heated seat module C3162-4, circuit 1060 (BK/LB), harness side and ground.
- Is the resistance less than 5 ohms between heated seat module and seat cushion heater and greater than 10,000 ohms between heated seat module and ground?
Yes
INSTALL a new left rear seat cushion heater. TEST the system for normal operation.
No
REPAIR the circuit. TEST the system for normal operation.
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O13 CHECK CIRCUIT 1064 (YE/LB) FOR AN OPEN OR SHORT TO GROUND
- Disconnect: Left Rear Seat Cushion Heater C3167.
- Measure the resistance between:
- left rear heated seat module C3162-6, circuit 1064 (YE/LB), harness side and left rear seat cushion heater C3167-1, circuit 1064 (YE/LB), harness side.
- left rear heated seat module C3162-6, circuit 1064 (YE/LB), harness side and ground.
- Is the resistance less than 5 ohms between the heated seat module and the seat cushion heater and greater than 10,000 ohms between the heated seat module and ground?
Yes
GO to O14.
No
REPAIR the circuit. TEST the system for normal operation.
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O14 CHECK CIRCUIT 1065 (WH/LB) FOR AN OPEN OR SHORT TO GROUND
- Disconnect: Left Rear Seat Backrest Heater C3168.
- Measure the resistance between:
- left rear heated seat module C3162-7, circuit 1065 (WH/LB), harness side and left rear seat backrest heater C3168-1, circuit 1065 (WH/LB), harness side.
- left rear heated seat module C3162-7, circuit 1065 (WH/LB), harness side and ground.
- Is the resistance less than 5 ohms between heated seat module and seat backrest heater and greater than 10,000 ohms between the heated seat module and ground?
Yes
GO to O15.
No
REPAIR the circuit. TEST the system for normal operation.
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O15 CHECK CIRCUIT 1064 (YE/LB) FOR AN OPEN OR SHORT TO GROUND BETWEEN THE HEATED SEAT MODULE AND SEAT BACKREST HEATER
- Measure the resistance between:
- left rear seat cushion heater C3167-4, circuit 1064 (YE/LB), harness side and left rear seat backrest heater C3168-2, circuit 1064 (YE/LB), harness side.
- left rear seat cushion heater C3167-4, circuit 1064 (YE/LB), harness side and ground.
- Is the resistance less than 5 ohms between seat cushion heater and seat backrest heater and greater than 10,000 ohms between seat cushion heater and ground?
Yes
GO to O16.
No
REPAIR the circuit. TEST the system for normal operation.
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O16 CHECK THE SEAT BACKREST HEATER RESISTANCE
- Measure the resistance between left rear seat backrest heater C3168 pins 1 and 2, component side.
- Is the resistance between 0.7 and 1.5 ohm?
Yes
INSTALL a new left rear seat cushion heater. TEST the system for normal operation.
No
INSTALL a new left rear seat backrest heater. TEST the system for normal operation.
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