GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Interior Lights Dimming Schematics

1

Did you perform the Lighting Systems Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Verify that the memory/heated switch backlighting is inoperative.

Does the memory/heated switch backlighting operate normally?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Are any other dimmable interior backlighting lamps inoperative?

Go to Interior Backlighting Inoperative

Go to Step 4

4

    • Place the headlamp switch in the PARK position.
    • Adjust the IP dimmer switch to the full intensity position.
    • Test for an open, high resistance, or short to voltage in the memory/heated seat switch illumination control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct a condition?

Go to Step 10

Go to Step 5

5

Use a test lamp connected to B+ to backprobe the memory/heated seat switch illumination control circuit terminal at the driver door module (DDM) connector.

Does the test lamp illuminate?

Go to Step 7

Go to Step 6

6

Inspect for poor connections at the harness connector of the DDM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 8

7

Inspect for poor connections at the harness connector of the memory/heated seat switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 9

8

Important: Perform the setup procedure for the driver door module (DDM).

Replace the DDM. Refer to Door Lock and Side Window Switch Replacement - Driver Side in Doors.

Did you complete the replacement?

Go to Step 10

--

9

Replace the memory/heated seat switch. Refer to Driver Seat Adjuster Memory Switch Replacement in Seats.

Did you complete the replacement?

Go to Step 10

--

10

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3