Circuit/System Testing

WARNING: This page is about a different car, the 2009 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.

Rear Heated Seat Switch Indicators Inoperative

Ignition OFF, disconnect the harness connector at the heated seat switch.
Ignition ON, verify that a test lamp illuminates between the supply voltage circuit terminal K and ground.
- If the test lamp does not illuminate, test the supply voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the body control module (BCM).
Ignition OFF, connect the harness connector at the heated seat switch.
Disconnect the X3, X4 harness connectors at the RHSM.
Ignition ON, connect a test lamp between the control circuits listed below and ground. The appropriate indicator should illuminate.
- Seat back and cushion mode indicator terminal 17 X4
- Seat back only mode indicator terminal 15 X4
- Low heat indicator terminal 5 X3
- Medium heat indicator terminal 16 X4
- High heat indicator terminal 4 X3
- If any indicator does not illuminate, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, test or replace the heated seat switch.
If all circuits test normal, replace the RHSM.

Heated Seat Switch Indicators Always On

Ignition OFF, disconnect the X3, X4 harness connectors at the RHSM.
Ignition ON, heated seats OFF, the heated seat switch mode indicators should not be illuminated.
- If illuminated, test the appropriate control circuit listed below for a short to ground. If the circuit tests normal, test or replace the heated seat switch.
  - Seat back and cushion mode indicator terminal 17 X4
  - Seat back only mode indicator terminal 15 X4
  - Low heat indicator terminal 5 X3
  - Medium heat indicator terminal 16 X4
  - High heat indicator terminal 4 X3
If all circuits test normal, replace the RHSM.