GM Service Manual Online
For 1990-2009 cars only

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Action

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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. Turn the ignition to the ON position.
  2. Place the headlamp switch in the PARK position.
  3. Turn the instrument panel (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 19

Go to Step 6

6

  1. Install the PANEL DIMMING fuse.
  2. Place the headlamp switch in the PARK position.
  3. Using a test lamp connected to ground, probe the parklamp switch ON signal circuit of the PANEL DIMMING fuse.

Does the test lamp illuminate?

Go to Step 7

Go to Step 18

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 15

8

  1. Connect the headlamp switch connector.
  2. Place the headlamp switch in the PARK position.
  3. Using a test lamp connected to ground, probe the instrument panel lamp fuse supply voltage 1 circuit of the headlamp switch.

Does the test lamp illuminate?

Go to Step 12

Go to Step 16

9

  1. Disconnect the inoperative component.
  2. Using a test lamp connected to ground, probe the instrument panel lamps dimmer switch signal circuit of the inoperative component.

Does the test lamp illuminate?

Go to Step 10

Go to Step 14

10

Using a test lamp connected to battery positive voltage, probe the ground circuit of the inoperative component.

Does the test lamp illuminate?

Go to Step 13

Go to Step 17

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 Diagnostic System Check - Vehicle in Vehicle DTC Information

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 22

Go to Step 20

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 22

Go to Step 21

14

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 22

--

15

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 22

--

16

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 22

--

17

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 22

--

18

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 22

--

19

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 22

--

20

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

Did you complete the repair?

Go to Step 22

--

21

Replace the inoperative component or bulb.

Did you complete the repair?

Go to Step 22

--

22

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2