GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

SCHEMATIC REFERENCE: Headlights Schematics

1

Did you perform the Light System Diagnostic System Check?

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Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the headlamp switch input parameter in the dash integration module (DIM) data list.
  4. Turn the headlamp switch ON and OFF.

Does the headlamp switch input parameter turn ON and OFF with the switch?

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Go to Step 8

Go to Step 3

3

  1. Connect a test lamp from the headlamp switch input circuit at the headlamp switch connector to battery positive voltage (B+).
  2. Turn the headlamp switch ON and OFF.

Does the test lamp turn ON and OFF with the headlamp switch?

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Go to Step 7

Go to Step 4

4

Test the headlamp switch ground circuit for high resistance or open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

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Go to Step 11

Go to Step 5

5

Inspect for poor connection at 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?

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Go to Step 11

Go to Step 6

6

Replace the headlamp switch. Refer to Turn Signal and Multifunction Switch Assembly - Disassemble - Off Vehicle in Steering Wheel and Column - Tilt.

Did you complete the replacement?

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Go to Step 11

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7

Test the headlamp switch input circuit for high resistance or open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 9

8

Test the control circuit of the low beam relay for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 9

9

Inspect for poor connection at the DIM. 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 11

Go to Step 10

10

Replace the DIM. Refer to Dash Integration Module Replacement in Body Control System.

Did you complete the replacement?

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Go to Step 11

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11

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