Pinpoint Test P: The Heated Seat Is Inoperative - Right Rear
Seats
Pinpoint Tests
Pinpoint Test P: The Heated Seat is Inoperative - Right Rear
Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information. Diagrams By Number
Normal Operation
The Smart Junction Box (SJB) supplies battery voltage to the rear heated seat module on circuit SBP18 (YE/RD), ignition voltage is supplied from the SJB on circuit CPB35 (YE/GY) and ground on circuit GD145 (BK/BU). When the heated seat control switch is pressed, a ground signal is sent to the heated seat module to command the system ON or OFF in HIGH heat mode or LOW heat mode. When commanded ON, a ground signal is supplied from the heated seat switch to the heated seat module on either circuit CHS52 (BU) (HIGH heat mode) or circuit CHS53 (WH/BN) (LOW heat mode) illuminating the switch indicator. The heated seat module also supplies voltage to the cushion and backrest heater mats on circuit CHS43 (GN/BU) and ground to the heater mats on circuit GD145 (BK/BU). 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 VHS45 (GY/BN) and monitors the return signal from the temperature sensor on circuit RHS41 (GN/BN) 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.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Heater mat
- Heated seat switch
- Heated seat module
PINPOINT TEST P: THE HEATED SEAT IS INOPERATIVE - RIGHT REAR
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P1 CHECK HEATED SEAT OPERATION
- Ignition ON.
- Operate the right rear heated seat in the HIGH and LOW setting.
- Does the seat operate in either setting?
Yes
If only the low setting operate, GO to P15.
If only the high setting operate, GO to P16.
No
GO to P2.
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P2 CHECK HEATED SEAT SWITCH INPUT
- Disconnect: Rear Heated Seat Module C3304a.
- Measure the resistance between rear heated seat module C3304a-8, circuit CHS50 (BU/GY), harness side and ground while pressing the high heated seat switch.
- Is the resistance less than 30 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 P4.
No
GO to P3.
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P3 CHECK HEATED SEAT SWITCH GROUND CIRCUIT FOR AN OPEN
- Disconnect: Rear Heated Seat Switch C321.
- Measure the resistance between right rear heated seat switch C321-1, circuit GD114 (BK/BU), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to P17.
No
REPAIR the circuit. TEST the system for normal operation.
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P4 CHECK THE VOLTAGE TO THE REAR HEATED SEAT MODULE FEED CIRCUIT
- Disconnect: Rear Heated Seat Module C3304b.
- Measure the voltage between rear heated seat module C3304b-3, circuit SBP18 (YE/RD), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to P5.
No
VERIFY SJB fuse 18 (20A) is OK. If OK, REPAIR the affected circuit. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. Diagrams By Number
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P5 CHECK THE PASSENGER HEATER MATS RESISTANCE AND HEATER MAT CIRCUITS FOR AN OPEN
- Measure the resistance between rear heated seat module C3304b-6, circuit CHS43 (GY/BU), harness side and ground.
- Is the resistance between 1.2 and 4 ohms?
Yes
GO to P11.
No
GO to P6.
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P6 CHECK HEATER GROUND CIRCUIT FOR AN OPEN
- Disconnect: Passenger Seat Backrest Heater Mat C3170.
- Measure the resistance between passenger backrest heater mat C3170-1, circuit GD145 (BK/BU), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to P7.
No
REPAIR the circuit. TEST the system for normal operation.
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P7 CHECK REAR SEAT CUSHION CIRCUIT FOR AN OPEN AND A SHORT TO GROUND
- Disconnect: Rear Seat Cushion C3045.
- Measure the resistance between:
- rear heated seat module C3304b-6, circuit CHS43 (GY/BU), harness side and rear seat cushion heater mat C3045-5, circuit CHS43 (GY/BU), harness side.
- rear heated seat module C3304b-6, circuit CHS43 (GY/BU), harness side and ground.
- Is the resistance less than 5 ohms between C3304b-6 and C3045-5, and greater than 10,000 ohms between C3304b-6 and ground?
Yes
GO to P8.
No
REPAIR the circuit. TEST the system for normal operation.
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P8 CHECK THE PASSENGER CUSHION HEATER MAT FOR AN OPEN
- Measure the resistance between rear heated seat cushion C3045 pin 6 and pin 5, component side.
- Is the resistance between 0.6 and 2 ohms?
Yes
GO to P9.
No
INSTALL a new rear seat cushion heater mat. REFER to Seat Cushion Heater Mat - Rear Seat Cushion Heater Mat - Rear. TEST the system for normal operation.
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P9 CHECK THE PASSENGER REAR SEAT CIRCUIT FOR AN OPEN
- Measure the resistance between rear seat cushion heater mat C3045-6, circuit CHS12 (YE/GN), harness side and rear seat backrest heater mat C3170-2, circuit CHS12 (YE/GN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to P10.
No
REPAIR the circuit. TEST the system for normal operation.
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P10 CHECK THE PASSENGER SEAT BACKREST HEATER MAT FOR AN OPEN
- Measure the resistance between right rear seat backrest heater C3170 pins 1 and 2, component side.
- Is the resistance between 0.6 and 2 ohms?
Yes
GO to P11.
No
INSTALL a new rear seat backrest heater mat. REFER to Seat Backrest Heater Mat - Rear Seat Backrest Heater Mat - Rear. TEST the system for normal operation.
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P11 CHECK THE TEMPERATURE SENSOR CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition ON.
- Measure the voltage between heated seat module C3304a-9, circuit VHS45 (GY/BN), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit. TEST the system for normal operation.
No
GO to P12.
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P12 CHECK THE HEATED SEAT TEMPERATURE SENSOR CIRCUITS FOR AN OPEN AND SHORT TO GROUND
- Ignition OFF.
- Connect: Rear Seat Cushion C3045.
- Measure the resistance between:
- heated seat module C3304a-9, circuit VHS45 (GY/BN), harness side and C3304a-12, circuit RHS41 (BK/BU), harness side.
- heated seat module C3304a-9, circuit VHS45 (GY/BN), harness side and ground.
- Is the resistance greater than 300 and less than 300,000 ohms between C3304a-3 and C3304a-12 and greater than 10,000 ohms between C3304a-12 and ground?
Yes
INSTALL a new rear heated seat module. REFER to Heated Seat Module - Rear Heated Seat Module - Rear. TEST the system for normal operation.
No
GO to P13.
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P13 CHECK THE HEATED SEAT TEMPERATURE SENSOR CIRCUIT VHS45 (GY/BN) FOR AN OPEN AND A SHORT TO GROUND
- Disconnect: Rear Seat Cushion C3045.
- Measure the resistance between:
- rear heated seat module C3304a-9, circuit VHS45 (GY/BN), harness side and rear seat cushion heater mat C3045-7, circuit VHS45 (GY/BN), harness side.
- rear heated seat module C3304a-9, circuit VHS45 (GY/BN), harness side and ground.
- Is the resistance less than 5 ohms between C3304a-9 and C3045-7, and greater than 10,000 ohms between C3304a-9 and ground?
Yes
GO to P14.
No
REPAIR the circuit. TEST the system for normal operation.
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P14 CHECK THE TEMPERATURE SENSOR FOR AN OPEN
- Measure the resistance between rear heated seat cushion C3045 pin 7 and pin 8, component side.
- Is the resistance between 300 ohms and 300,000 ohms?
Yes
REPAIR ground circuit RHS41 (GN/BN). TEST the system for normal operation.
No
INSTALL a new rear seat cushion heater mat. REFER to Seat Cushion Heater Mat - Rear Seat Cushion Heater Mat - Rear. TEST the system for normal operation.
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P15 CHECK THE HEATED SEAT SWITCH HIGH CIRCUIT FOR AN OPEN AND A SHORT TO GROUND
- Disconnect: Rear Heated Seat Module C3304a.
- Disconnect: Heated Seat Switch C321.
- Measure the resistance between:
- rear heated seat module C3304a-8, circuit CHS50 (BU/GY), harness side and right rear heated seat switch C321-6, circuit CHS50 (BU/GY), harness side.
- rear heated seat module C3304a-8, circuit CHS50 (BU/GY), harness side and ground.
- Is the resistance less than 5 ohms between the heated seat module and the heated seat switch and greater than 10,000 ohms between the heated seat module and ground?
Yes
GO to P17.
No
REPAIR the circuit. TEST the system for normal operation.
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P16 CHECK THE HEATED SEAT SWITCH LOW CIRCUIT FOR AN OPEN AND A SHORT TO GROUND
- Disconnect: Heated Seat Switch C321.
- Measure the resistance between:
- rear heated seat module C3304a-7, circuit CHS51 (YE/GY), harness side and right rear heated seat switch C321-2, circuit CHS51 (YE/GY), harness side.
- rear heated seat module C3304a-7, circuit CHS51 (YE/GY), harness side and ground.
- Is the resistance less than 5 ohms between the heated seat module and the heated seat switch and greater than 10,000 ohms between the heated seat module and ground?
Yes
GO to P17.
No
REPAIR the circuit. TEST the system for normal operation.
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P17 CHECK THE REAR HEATED SEAT SWITCH
- Disconnect: Heated Seat Switch C320.
- Measure the resistance between rear heated seat switch pins, component side, while pressing the indicated switch buttons and compare the results to the table.
- Is the resistance less than 30 ohms with the switch buttons depressed and greater than 10,000 ohms with the switch buttons released?
Yes
INSTALL a new left rear heated seat module. REFER to Heated Seat Module - Rear Heated Seat Module - Rear. TEST the system for normal operation.
No
INSTALL a new rear heated seat switch. REFER to Heated Seat Switch - Rear Heated Seat Switch - Rear.
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