GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

Connector End View Reference: Master Electrical Component List in Wiring Systems

1

Did you review the exterior lighting description and operation and perform the necessary inspections?

Go to Step 2

Go to Diagnostic Starting Point - Lighting Systems

2

Place the headlamp switch in the PARK position.

Do the park lamps illuminate?

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

Go to Step 3

3

  1. Remove the inoperative park lamp bulb.
  2. Connect a test lamp between the park lamp supply voltage circuit of the inoperative park lamp bulb and the ground circuit of the inoperative park lamp bulb.
  3. Turn ON the park lamps.

Does the test lamp illuminate?

Go to Step 8

Go to Step 4

4

Test the park lamp supply voltage circuit for high resistance, an open or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 5

5

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

Did you find and correct the condition?

Go to Step 12

Go to Step 6

6

  1. Disconnect the headlamp switch.
  2. Probe the battery positive voltage circuit of the park lamps with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

Go to Step 7

Go to Step 9

7

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 12

Go to Step 10

8

Inspect for poor connections at the inoperative park lamp 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 12

Go to Step 11

9

Repair the open, high resistance or short to ground in the battery positive voltage circuit of the headlamp switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 12

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10

Replace the headlamp switch. Refer to Headlamp Switch Replacement .

Did you complete the replacement?

Go to Step 12

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11

Replace the inoperative park lamp bulb.

Did you complete the replacement?

Go to Step 12

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12

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2