GM Service Manual Online
For 1990-2009 cars only

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Action

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

Connector End View Reference: Lighting Systems Connector End Views , Steering Wheel and Column Connector End Views in Steering Wheel and Column, 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

  1. Turn ON the ignition, with the engine OFF.
  2. Place the headlamp switch in the ON position.
  3. Place the headlamp dimmer switch in the FLASH TO PASS position.

Does the flash to pass function operate properly?

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

Go to Step 3

3

Place the headlamp dimmer switch in the HIGH BEAM position.

Do the high beam headlamps operate properly?

Go to Step 4

Go to Headlamps Inoperative - High Beams

4

  1. With a scan tool, observe the Flash to Pass Switch parameter in the dash integration module (DIM) inputs data list.
  2. Place the headlamp dimmer switch in the FLASH TO PASS position.

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

Go to Step 7

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Disconnect the headlamp dimmer switch.
  3. Connect a 3-amp fused jumper between the flash to pass switch signal circuit of the headlamp dimmer switch and a good ground.
  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 6

Go to Step 8

6

Connect a 3-amp fused jumper between the flash to pass switch signal circuit of the headlamp dimmer switch and the ground circuit of the headlamp dimmer switch.

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

Go to Step 9

Go to Step 11

7

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 14

Go to Step 10

8

Test for an open or high resistance in the flash to pass signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 10

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 14

Go to Step 12

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 14

Go to Step 13

11

Repair 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 14

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12

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 14

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13

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

Did you complete the replacement?

Go to Step 14

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14

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2