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: Lighting Systems Connector End Views or Computer/Integrating Systems Connector End Views in Computer/Integrating 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

Verify that the high beam headlamps are inoperative.

Do the high beam headlamps operate normally?

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

Go to Step 3

3

Is only one high beam headlamp inoperative?

Go to Step 4

Go to Step 5

4

  1. Inspect the inoperative bulb for an open filament and connector for poor terminal contact and replace/repair as necessary. Refer to Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement or Wiring Repairs in Wiring Systems.
  2. If the condition above does not exist, repair the open, high resistance or short to ground in the high beam headlamp supply voltage circuit or ground circuit to the inoperative lamp. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 13

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5

Test the headlamp dimmer switch high beam signal and ground circuits for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct a condition?

Go to Step 13

Go to Step 6

6

  1. Place the headlamp switch in the ON position.
  2. Connect a fused jumper from ground to the headlamp high beam dimmer switch signal terminal of the turn signal/multifunction switch connector.

Do the high beam headlamps illuminate?

Go to Step 8

Go to Step 7

7

Connect a fused jumper from B+ voltage to the beam select relay control circuit terminal at the beam select relay in the underhood fuse block.

Do the high beam headlamps illuminate?

Go to Step 9

Go to Step 11

8

Inspect for poor connections at the harness connector of the turn signal/multifunction switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 12

9

Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 10

10

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

Did you complete the replacement?

Go to Step 13

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11

Replace the beam select relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the repair?

Go to Step 13

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12

Replace the turn signal/multifunction switch. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column.

Did you complete the repair?

Go to Step 13

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13

  1. Use the scan tool in order to clear any induced DTCs.
  2. Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3