GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

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

1

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

Do the high beam headlamps operate properly?

Go to Step 3

Go to Headlamps Inoperative - High Beams

3

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Flash to Pass Switch parameter in the Dash Integration Module (DIM) inputs data list.
  4. Turn the flash to pass switch ON and OFF.

Does the Flash to Pass Switch parameter turn ON and OFF with the switch?

Go to Step 4

Go to Step 5

4

With a scan tool, command the HDLP HI BM relay ON and OFF.

Do the high beam headlamps turn ON and OFF with each command?

Go to Step 10

Go to Step 6

5

  1. Turn OFF the ignition.
  2. Disconnect the headlamp dimmer switch.
  3. Connect a 3 amp fused jumper between the flash to pass input circuit of the headlamp dimmer switch and the ground circuit of the headlamp dimmer switch.
  4. Turn ON the ignition, with the engine OFF.

Does the scan tool indicate that the Flash to Pass Switch parameter is ON?

Go to Step 9

Go to Go to Step 7

6

Test for an open or high resistance in the headlamp high beam relay control circuit. 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

7

Test for an open or high resistance in the flash to pass input circuit of the headlamp dimmer 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 8

8

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

Did you find and correct the condition?

Go to Step 13

G to Step 9

9

Inspect for poor connection 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 13

Go to Step 11

10

Inspect for poor connections 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 13

Go to Step 12

11

Replace the headlamp dimmer switch. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column.

Did you complete the replacement?

Go to Step 13

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12

Important:: Perform the setup procedure for the Dash Integration Module (DIM). Refer to Body Control Module (BCM) Programming/RPO Configuration .

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

Did you complete the replacement?

Go to Step 13

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13

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2