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 inoperative.

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

Inspect the PARK LP fuse in the body relay block.

Is the fuse good?

Go to Step 4

Go to Step 5

4

Disconnect the headlamp switch and connect a fused jumper between the battery positive voltage circuit input terminal and the park lamps switch signal circuit output terminal at the headlamp switch connector.

Do the marker, license, and tail lamps illuminate?

Go to Step 8

Go to Step 6

5

Remove the park lamp relay and test for a short to ground in the following circuits. Refer to Circuit Testing in Wiring Systems:

    • Battery positive voltage
    • Park lamps switch signal

Was a problem found?

Go to Step 7

Go to Step 9

6

Repair the open or high resistance in the following circuits. Refer to Wiring Repairs in Wiring Systems:

    • Battery positive voltage
    • Park lamps switch signal

Is the repair complete?

Go to Step 10

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7

Repair the short to ground in one of the following circuits. Refer to Wiring Repairs in Wiring Systems:

    • Battery positive voltage
    • Park lamps switch signal

Is the repair complete?

Go to Step 10

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8

Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Is the repair complete?

Go to Step 10

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9

Replace the park lamp relay.

Is the repair complete?

Go to Step 10

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10

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3