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

  1. Turn ON the ignition, with the engine OFF.
  2. Place the headlamp switch in the park position.
  3. Open the hood.

Does the underhood lamp 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

  1. Disconnect the underhood lamp bulb.
  2. Connect a test lamp between the supply voltage circuit of the underhood lamp bulb and the ground circuit of the underhood lamp bulb .

Does the test lamp illuminate?

Go to Step 8

Go to Step 5

5

  1. Disconnect the underhood lamp assembly.
  2. Connect a test lamp between the supply voltage circuit of the underhood lamp and the ground circuit of the underhood lamp.

Does the test lamp illuminate?

Go to Step 7

Go to Step 6

6

Test for an open or high resistance in the supply voltage circuit of the underhood lamp assembly. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 9

7

Inspect for poor connections at the harness connector of the underhood lamp assembly. 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 harness connector of the underhood 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 an open or high resistance in the ground circuit of the underhood lamp assembly. 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 underhood lamp assembly. Refer to Underhood Lamp Replacement .

Is the underhood lamp replacement complete?

Go to Step 12

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11

Replace the underhood lamp bulb. Refer to Underhood Lamp Replacement .

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