Pinpoint Test W: The Heated Seat Does Not Operate Correctly - Left Rear Seat

Seats

Pinpoint Test W: The Heated Seat Does Not Operate Correctly - Left Rear Seat Does Heat but the Heated Seat Indicator Does Not Illuminate When Pressed

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

Normal Operation

Upon receiving a pulsed ground from the rear HVAC module, the rear heated seat module decreases one setting (the sequence is high, low, off, high). There are 2 circuits between the rear heated seat module and rear HVAC module that control the indicator operation. When voltage is supplied to the rear HVAC module on either of these circuits the appropriate indicator illuminates. When a heated seat is set to high, both indicators on the heated seat control button illuminate. When a heated seat is set to low, only the lower indicator illuminates. When a heated seat is set to off, neither is illuminated.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- Rear HVAC module

- Rear heated seat module

PINPOINT TEST W : THE HEATED SEAT DOES NOT OPERATE CORRECTLY - LEFT REAR SEAT DOES HEAT BUT THE HEATED SEAT INDICATOR DOES NOT ILLUMINATE WHEN PRESSED

W1 CHECK THE INDICATOR CIRCUITS FOR A SHORT TO GROUND

- Disconnect: Rear HVAC Module C3198.

- Disconnect: Heated Seat Module C3304A.

- Measure the resistance between:
- heated seat module C3304A-4, circuit CHS49 (VT), harness side and ground.

- heated seat module C3304A-5, circuit CHS48 (YE), harness side and ground.






Are the resistances greater than 10,000 ohms?

Yes
GO to W2.

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

W2 CHECK THE INDICATOR CIRCUITS FOR AN OPEN

- Measure the resistance between:
- rear heated seat module C3304A-4, circuit CHS49 (VT), harness side and rear HVAC module C3198-14, circuit CHS49 (VT), harness side.

- rear heated seat module C3304A-5, circuit CHS48 (YE), harness side and rear HVAC module C3198-15, circuit CHS48 (YE), harness side.






Are the resistances less than 5 ohms?

Yes
GO to W3.

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

W3 CHECK THE HEATED SEAT HIGH INDICATOR

- Connect: Rear HVAC Module C3198.

- Disconnect: Heated Seat Module C3304B.

- Ignition ON.

- Connect a fused jumper lead between rear heated seat module C3304A-5, circuit CHS48 (YE), harness side and C3304B-1, circuit SBP40 (VT/RD), harness side.





Does the high indicator illuminate on the rear HVAC module?

Yes
GO to W4.

No
INSTALL a new HVAC module.

W4 CHECK THE HEATED SEAT LOW INDICATOR

- Connect a fused jumper lead between heated seat module C3304A-4, circuit CHS49 (VT), harness side and C3304B-1, circuit SBP40 (VT/RD), harness side.





Does the low indicator illuminate on the rear HVAC module?

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

No
INSTALL a new rear HVAC module. TEST the system for normal operation.