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 park lamps.
  2. Open and close 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. Turn ON the ignition, with the engine OFF.
  3. Turn ON the park lamps.
  4. Connect a test lamp between the instrument panel lamp fuse supply voltage - 1 circuit of the underhood lamp bulb and the underhood lamp bulb ground circuit.

Does the test lamp illuminate?

Go to Step 8

Go to Step 5

5

  1. Disconnect the underhood lamp.
  2. Connect a test lamp between the instrument panel lamp fuse supply voltage - 1 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 the instrument panel lamp fuse supply voltage - 1 circuit for an high resistance or a 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 9

7

Inspect for poor connections at the harness connector of the underhood lamp. 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 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 the high resistance or an open in the ground circuit of the underhood lamp. 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.

Did you complete the replacement?

Go to Step 12

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11

Replace the underhood 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