GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights 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 switch ON.
  2. Place the headlamp switch in the OFF position.
  3. Verify that the park lamps are OFF.

Are the park lamps OFF?

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

Go to Step 3

3

  1. Use the scan tool in order to turn off the park lamps.
  2. Select PARK LAMPS from the Light Test Menu under Special Functions on the scan tool.
  3. With the ignition on, press the OFF button and the ON button on the scan tool in order to turn the park lamps on and off.
  4. Monitor the scan tool while pressing the ON and OFF buttons. The scan tool can tell you the status of the BCM when either the ON or OFF button has been pressed.

Do the park lamps turn OFF when commanded by the BCM?

Go to Step 4

Go to Step 5

4

Test the park lamp on and off input circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 7

5

Remove the park lamp relay.

Do the park lamps still illuminate?

Go to Step 6

Go to Step 8

6

Locate a short to B+ in the park lamp supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 9

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7

Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Did you complete the repair?

Go to Step 9

--

8

Replace the park lamp relay.

Did you complete the repair?

Go to Step 9

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9

  1. Connect all connectors and components that were previously disconnected.
  2. Verify that the park lamps operate properly.

Do the park lamps operate properly?

System OK

Go to Step 2