GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights 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 marker, license and tail lamps are always on.

Do the marker, license and tail lamps operate normally?

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

Go to Step 3

3

Disconnect the headlamp switch.

Do the marker, license, and tail lamps remain illuminated?

Go to Step 4

Go to Step 6

4

Test for a short to voltage in the park lamps supply voltage or a short to ground in the park lamp relay control circuit. Refer to Circuit Testing in Wiring Systems.

Was a problem found?

Go to Step 5

Go to Step 7

5

Repair the short to voltage in the park lamps supply voltage or a short to ground in the park lamp relay control circuit. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

Go to Step 8

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6

Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Is the repair complete?

Go to Step 8

--

7

Replace the park lamp relay.

Is the repair complete?

Go to Step 8

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8

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3