GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics

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

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Place the headlamp switch in the OFF position.
  2. Install a scan tool.
  3. Turn ON the ignition, with the engine OFF.
  4. With the scan tool, WOW the instrument cluster.
  5. Observe the high beam indicator on the instrument cluster.

Does the high beam indicator illuminate during Instrument cluster WOW?

Go to Step 3

Go to Step 7

3

  1. Place the headlamp switch in the HEAD position.
  2. Place the headlamp dimmer switch in the HIGH BEAM position.
  3. Observe the high beam indicator.

Does the high beam indicator illuminate?

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

Go to Step 4

4

Do the high beam headlamps illuminate?

Go to Step 5

Go to Headlamps Inoperative - High Beams

5

With a scan tool go to BCM Inputs, verify the high beam ON switch parameters.

Do the parameters show the high beam switch in the ON position?

Go to Step 8

Go to Step 6

6

Repair a poor connection or an open in the BCM class 2 serial data circuit. Refer to Wiring Repairs and to Connector Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 9

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7

Replace the instrument cluster. Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming.

Did you complete the replacement?

Go to Step 9

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8

Replace the body control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming.

Did you complete the replacement?

Go to Step 9

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9

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2