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 System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn the ignition to the ON position.
  2. Place the headlamp switch in the PARK position.
  3. Turn the I/P lamp dimmer switch to a high position.

Are all the incandescent backlighting lamps and VF dimming lamps on?

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

Go to Step 3

3

Are all of the incandescent backlighting lamps inoperative?

Go to Step 5

Go to Step 4

4

Is only one of the incandescent backlighting components inoperative?

Go to Step 9

Go to Step 11

5

Check the PANEL DIMMING fuse for an open.

Is the PANEL DIMMING fuse open?

Go to Step 20

Go to Step 6

6

  1. Install the PANEL DIMMING fuse.
  2. Place the headlamp switch in the PARK position.
  3. Backprobe the parklamp switch on signal circuit of the PANEL DIMMING fuse with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 7

Go to Step 19

7

  1. Disconnect the headlamp switch.
  2. Connect a fused jumper between the instrument panel lamps dimmer switch circuit and battery voltage of the headlamp switch.

Do the backlighting lamps illuminate?

Go to Step 8

Go to Step 16

8

  1. Connect the headlamp switch connector.
  2. Place the headlamp switch in the PARK position.
  3. Backprobe the instrument panel lamp fuse supply voltage --1 circuit of the headlamp switch with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 12

Go to Step 17

9

  1. Disconnect the inoperative component.
  2. Probe the instrument panel lamps dimmer switch signal circuit of the inoperative component with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 10

Go to Step 15

10

Probe the ground circuit of the inoperative component with a test lamp that is connected to battery voltage.

Does the test lamp illuminate?

Go to Step 13

Go to Step 18

11

If the vacuum florescent lighting does not illuminate in a component, determine if the component is operating properly. Refer to the appropriate Description and Operation:

    • The Radio/Audio System Description and Operation in Entertainment
    • The Instrument Cluster Description and Operation in Instrument Panel, Gages, and Console
    • The Air Delivery Description and Operation in HVAC Systems - Manual

Does the component operate properly?

Go to Step 13

Go to Step 14

12

Inspect for poor connections at the harness connector of the headlamp switch. 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 23

Go to Step 21

13

Inspect for poor connections at the harness connector of the inoperative component or bulb. 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 23

Go to Step 22

14

Refer to the appropriate procedure:

    •  Diagnostic Starting Point - Entertainment in Entertainment
    •  Diagnostic System Check - Audible Warnings in Instrument Panel, Gages, and Console
    •  Diagnostic System Check - HVAC Systems - Manual in HVAC Systems - Manual

Did complete the repair?

Go to Step 23

--

15

Repair a high resistance or an open in instrument panel lamps dimmer switch signal circuit of the inoperative component. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

16

Repair a high resistance or an open in the instrument panel lamps dimmer switch signal circuit of the headlamp switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

17

Repair a high resistance or an open in the instrument panel lamp fuse supply voltage --1 circuit of the headlamp switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

18

Repair a high resistance or an open in the ground circuit of the inoperative component. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

19

Repair a high resistance or an open in the park lamps switch on signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

20

Repair a short to ground in the instrument panel lamp fuse supply voltage - 1 circuit or the instrument panel lamps dimmer switch circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 23

--

21

Replace the headlamp switch. Refer to Headlamp Switch Replacement in Instrument Panel, Gages, and Console.

Did you complete the repair?

Go to Step 23

--

22

Replace the inoperative component or bulb.

Did you complete the repair?

Go to Step 23

--

23

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2