Pinpoint Test Z: The Heated Seat is Inoperative/Does Not Operate Correctly - Right Rear

Seating

Pinpoint Test Z: The Heated Seat is Inoperative/Does Not Operate Correctly - Right Rear

Refer to Wiring Diagram Set 119, Climate Controlled Seats for schematic and connector information. Diagrams By Number

Normal Operation

The heated seat module receives ignition voltage, battery voltage and ground. A ground signal is sent from the heated seat switch to the heated seat module to command the system ON or OFF on circuit CHS50 (HI heat mode) or CHS51 (LOW heat mode). The heated seat module supplies voltage to the cushion and backrest heater mats on circuit CHS43 and ground on GD145. The cushion and backrest heater mats are connected in series and operate together. The heated seat module supplies a reference voltage to the temperature sensor on circuit VHS45 and return on RHS41.

The heated seat module faults detected will be:

- a heater feed circuit short to battery, ground or open.

- sensor circuit short to battery or open.

- heated seat switch stuck closed to ground.

This pinpoint test is intended to diagnose the following:

- Fuse

- Wiring, terminals or connectors

- Heater mat

- Heated seat switch

- Heated seat module

PINPOINT TEST Z : THE HEATED SEAT IS INOPERATIVE/DOES NOT OPERATE CORRECTLY - RIGHT REAR

Z1 CHECK FOR VOLTAGE TO THE REAR HEATED SEAT MODULE

- Disconnect: Heated Seat Module C3304B.

- Ignition ON.

- Measure the voltage between:
- rear heated seat module C3304B-2, circuit CBP35 (YE/GY), harness side and ground.

- rear heated seat module C3304B-3, circuit SBP18 (YE/RD), harness side and ground.

Are the voltages greater than 10 volts?

Yes
GO to Z2.

No
VERIFY Smart Junction Box (SJB) fuses 18 (20A) and 35 (10A) are OK. If OK, REPAIR the affected circuit. 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

Z2 CHECK THE REAR HEATED SEAT MODULE GROUND CIRCUIT FOR AN OPEN

- Ignition OFF.

- Measure the resistance between rear heated seat module C3304B-5, circuit GD145 (BK/BU), harness side and ground.

Is the resistance less than 5 ohms?

Yes
GO to Z3.

No
REPAIR the circuit. TEST the system for normal operation.

Z3 CHECK FOR RIGHT REAR HEATED SEAT OPERATION

- Connect: Heated Seat Module C3304B.

- Ignition ON.

- Operate the right rear heated seat switch.

Does the seat operate in either setting?

Yes
If only the LOW setting operates, GO to Z19.

If only the HIGH setting operates, GO to Z20.

No
GO to Z4.

Z4 CHECK THE RIGHT REAR HEATED SEAT SWITCH INPUT

- Ignition OFF.

- Disconnect: Rear Heated Seat Module C3304A.

- Measure resistance between rear heated seat module C3304A-8, circuit CHS50 (BU/GY), harness side and ground while pressing the heated seat switch to high.

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 Z6.

No
GO to Z5.

Z5 CHECK THE RIGHT REAR HEATED SEAT SWITCH GROUND CIRCUIT FOR AN OPEN

- Disconnect: Right Rear Heated Seat Switch C321.

- Measure 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 Z21.

No
REPAIR the circuit. TEST the system for normal operation.

Z6 CHECK THE HEATER MAT INPUT CIRCUIT FOR A SHORT TO VOLTAGE

- Ignition ON.

- Measure the voltage between heated seat module C3304B-6, circuit CHS43 (GY/BU), harness side and ground.

Is any voltage present?

Yes
REPAIR the circuit. TEST the system for normal operation.

No
GO to Z7.

Z7 CHECK THE RIGHT REAR 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.

- Repeat the resistance measurement between rear heated seat module C3304B-6, circuit CHS43 (GY/BU), harness side and ground with an occupant or weight on the seat and check for an intermittent open.

Is the resistance between 1.2 and 4 ohms?

Yes
GO to Z15.

No
GO to Z8.

Z8 CHECK THE RIGHT REAR HEATER MATS GROUND CIRCUIT FOR AN OPEN

- Disconnect: Right Rear Seat Backrest Heater Mat C3170.

- Measure 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 Z9.

No
REPAIR the circuit. TEST the system for normal operation.

Z9 CHECK THE RIGHT REAR HEATER INPUT CIRCUIT FOR AN OPEN OR SHORT TO GROUND

- Disconnect: Right Rear Seat Cushion Heater Mat C3169.

- Measure resistance between:
- rear heated seat module C3304B-6, circuit CHS43 (GY/BU), harness side and right rear seat cushion heater mat C3169-1, 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 C3169-1, and greater than 10,000 ohms between C3304B-6 and ground?

Yes
GO to Z10.

No
REPAIR the circuit. TEST the system for normal operation.

Z10 CHECK THE RIGHT REAR CUSHION HEATER MAT FOR AN OPEN

- Measure the resistance between rear heated seat cushion C3169 pins 1 and 4, component side.

Is the resistance between 0.6 and 2 ohms?

Yes
GO to Z11.

No
INSTALL a new rear seat cushion heater mat. REFER to Seat Cushion Heater Mat - Rear . TEST the system for normal operation.

Z11 CHECK THE RIGHT REAR CUSHION HEATER MAT FOR AN OPEN

- Carry out the following measurements with an occupant in the seat and check for an open heater mat with weight on the seat.

- Measure the resistance between rear heated seat cushion C3169 pins 1 and 4, component side.

Is the resistance between 0.6 and 2 ohms?

Yes
GO to Z12.

No
INSTALL a new rear seat cushion heater mat. REFER to Seat Cushion Heater Mat - Rear . TEST the system for normal operation.

Z12 CHECK THE RIGHT REAR HEATED SEAT CIRCUIT FOR AN OPEN OR SHORT TO GROUND

- Measure resistance between:
- right rear seat cushion heater mat C3169-4, circuit CHS12 (YE/GN), harness side and right rear seat backrest heater mat C3170-2, circuit CHS12 (YE/GN), harness side.

- right rear seat cushion heater mat C3169-4, circuit CHS12 (YE/GN), harness side and ground.

Is the resistance less than 5 ohms between C3169-4 and C3170-2, and greater than 10,000 ohms between C3169-4 and ground?

Yes
GO to Z13.

No
REPAIR the circuit. TEST the system for normal operation.

Z13 CHECK THE RIGHT REAR BACKREST HEATER MAT FOR AN OPEN

- Measure 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 Z14.

No
INSTALL a new rear seat backrest heater mat. REFER to Seat Backrest Heater Mat - Rear . TEST the system for normal operation.

Z14 CHECK THE RIGHT REAR BACKREST HEATER MAT FOR AN OPEN

- Carry out the following measurements with an occupant in the seat and check for an open heater mat with weight on the seat.

- Measure resistance between right rear seat backrest heater C3170 pins 1 and 2, component side.

Is the resistance between 0.6 and 2 ohms?

Yes
The fault is intermittent, CHECK for causes of the intermittent fault. INSPECT the connectors, terminals and wiring. ATTEMPT to recreate the fault by flexing the wire harness and operating the system. CHECK the electrical connectors for corrosion, poor pin contact or pushed-out pins. REPAIR any intermittent concerns found and TIGHTEN any loose connector pins. TEST the system for normal operation.

No
INSTALL a new rear seat backrest heater mat. REFER to Seat Backrest Heater Mat - Rear . TEST the system for normal operation.

Z15 CHECK THE RIGHT REAR HEATED SEAT 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. GO to Z18 to check the temperature sensor for damage. If temperature sensor is OK, TEST the system for normal operation.

No
GO to Z16.

Z16 CHECK THE TEMPERATURE SENSOR OUTPUT CIRCUIT FOR AN OPEN AND SHORT TO GROUND

- Ignition OFF.

- Disconnect: Right Rear Seat Cushion Heater Mat C3169.

- Measure the resistance between:
- heated seat module C3304A-9, circuit VHS45 (GY/BN), harness side and seat cushion heater mat C3169-2, circuit VHS45 (GY/BN), harness side.

- heated seat module C3304A-9, circuit VHS45 (GY/BN), harness side and ground.

Is the resistance less than 5 ohms between C3304A-9 and C3169-2, and greater than 10,000 ohms between C3304A-9 and ground?

Yes
GO to Z17.

No
REPAIR the circuit. TEST the system for normal operation.

Z17 CHECK THE RIGHT REAR HEATED SEAT TEMPERATURE SENSOR CIRCUITS FOR AN OPEN OR SHORT TO GROUND

- Connect: Right Rear Seat Cushion Heater Mat C3169.

- Measure resistance between:
- rear heated seat module C3304A-9, circuit VHS45 (GY/BN), harness side and C3304A-12, circuit RHS41 (GN/BN), harness side.

- repeat the measurement between rear heated seat module C3304A-9, circuit VHS45 (GY/BN), harness side and C3304A-12, circuit RHS41 (GN/BN), harness side with an occupant or weight on the seat and check for an intermittent open.

- rear heated seat module C3304A-9, circuit VHS45 (GY/BN), harness side and ground.

- Repeat the resistance measurement between rear heated seat module C3304B-6, circuit CHS43 (GY/BU), harness side and ground with an occupant or weight on the seat and check for an intermittent open.

Is the resistance greater than 300 and less than 300,000 ohms between C3304A-9 and C3304A-12 and greater than 10,000 ohms between C3304A-9 and ground?

Yes
GO to Z19.

No
GO to Z18.

Z18 CHECK THE RIGHT REAR TEMPERATURE SENSOR FOR AN OPEN

- Ignition OFF.

- Disconnect: Right Rear Seat Cushion Heater Mat C3169.

- Measure resistance between rear heated seat cushion C3169 pin 2 and pin 3, component side.

- Repeat the resistance measurement between rear heated seat cushion C3169 pin 2 and pin 3, component side with an occupant or weight on the seat and check for an intermittent open.

Is the resistance between 8,000 ohms and 15,000 ohms?

Yes
REPAIR 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 . TEST the system for normal operation.

Z19 CHECK THE RIGHT HEATED SEAT SWITCH HIGH CIRCUIT FOR AN OPEN OR SHORT TO GROUND

- Ignition OFF.

- Disconnect: Rear Heated Seat Module C3304A.

- Disconnect: Right Rear Heated Seat Switch C321.

- Measure resistance between:
- rear heated seat module C3304A-8, circuit CHS50 (BU/GY), harness side and right rear heated seat switch C321-2, 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 Z21.

No
REPAIR the circuit. TEST the system for normal operation.

Z20 CHECK THE RIGHT REAR HEATED SEAT SWITCH LOW CIRCUIT FOR AN OPEN OR SHORT TO GROUND

- Ignition OFF.

- Disconnect: Rear Heated Seat Module C3304A.

- Disconnect: Right Rear Heated Seat Switch C321.

- Measure resistance between:
- rear heated seat module C3304A-7, circuit CHS51 (YE/GY), harness side and right rear heated seat switch C321-6, circuit CHS51 (YE/GY), harness side.

- rear heated seat module C3304A-7, circuit CHS51 (YE/GY), harness side and ground.

Is the heated seat switch OK?

Yes
INSTALL a new rear heated seat module. REFER to Heated Seat Module - Rear . TEST the system for normal operation.

No
INSTALL a new rear heated seat switch. REFER to Heated Seat Switch - Rear .