GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Interior Lights Dimming Schematics

Connector End View Reference: Master Electrical Component List in Wiring Systems

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Place the ignition switch in the ON position.
  2. Turn the headlamp switch to the HEAD position.
  3. Rotate the instrument panel (I/P) dimmer switch to the high and then low illumination settings.

Do all dimming lamps operate properly?

Go to Testing for Intermittent Conditions and Poor Connections

in Wiring Systems

Go to Step 3

3

Do the park lamp and headlamps illuminate?

Go to Step 4

Go to Symptoms - Lighting Systems

4

Is only one dimming lamp inoperative?

Go to Step 5

Go to Step 6

5

Test the supply voltage circuit and the ground circuit of the inoperative lamp for high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 7

6

Test the instrument panel lamp supply voltage circuit for high resistance, open, or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 8

7

Inspect for poor connections at the harness connector of the inoperative component. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 9

8

Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 10

9

Replace the inoperative component.

Did you complete the replacement?

Go to Step 11

--

10

Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 11

--

11

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2