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

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 ON the ignition, with the engine OFF.
  2. Place the headlamp switch in the PARK position.
  3. Operate the instrument panel (I/P) lamp dimmer switch from minimum to maximum.

Does the interior backlighting operate properly?

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

Go to Step 3

3

Do the park lamps operate properly?

Go to Step 4

Go to Park Lamps Inoperative

4

Are all of the interior backlighting lamps inoperative?

Go to Step 9

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Disconnect the component with the inoperative backlight lamp.
  3. Connect a test lamp between the backlight lamp control circuit of the component with the inoperative backlight lamp and the ground circuit of the component with the inoperative backlight lamp.
  4. Turn ON the ignition, with the engine OFF.
  5. Place the headlamp switch in the PARK position.
  6. Operate the I/P lamp dimmer switch from minimum to maximum.

Does the test lamp illuminate?

Go to Step 10

Go to Step 6

6

Test the backlight lamps control circuit of the inoperative backlight lamp for an open, high resistance, or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 7

7

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

Did you find and correct the condition?

Go to Step 14

Go to Step 8

8

Inspect for poor connections at the harness connector of the appropriate control module for the inoperative backlight lamp. 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 14

Go to Step 13

9

Inspect for poor connections at the harness connector of the instrument panel cluster (IPC). 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 14

Go to Step 12

10

Inspect for poor connections at the harness connector of the component with inoperative backlight lamp. 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 14

Go to Step 11

11

  1. Replace the inoperative backlight bulb(s) in the component if they are replaceable. See the appropriate systems operation and description.
  2. If the bulb is not replaceable replace the component with the inoperative backlight lamps.

Did you complete the replacement?

Go to Step 14

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12

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

Did you complete the replacement?

Go to Step 14

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13

Replace the appropriate control module for the inoperative backlight lamp. Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming.

Did you complete the replacement?

Go to Step 14

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14

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2