GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Did you perform the Lighting System Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the headlamp dimmer switch connector.

Did the high beam headlamps turn OFF?

--

Go to Step 8

Go to Step 3

3

Test the Flash to Pass 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 10

Go to Step 4

4

Disconnect the lighting control module (LCM).

Did the high beam headlamps turn off?

--

Go to Step 6

Go to Step 5

5

Repair the short to voltage in the high beam headlamp power feed circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

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Go to Step 10

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6

Inspect for poor connections at the LCM. 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 10

Go to Step 7

7

Replace the LCM. Refer to Lamp Control Module Replacement .

Did you complete the replacement?

--

Go to Step 10

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8

Inspect for poor connections at the headlamp dimmer 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 10

Go to Step 9

9

Replace the headlamp dimmer switch. Refer to Multifunction Turn Signal Lever Replacement - On Vehicle in Steering Wheel and Column.

Did you complete the replacement?

--

Go to Step 10

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10

Operate the system in order to verify the repair.

Did you find and correct the condition?

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System OK

Go to Step 2