GM Service Manual Online
For 1990-2009 cars only

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

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

1

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn ON the ignition, with the engine OFF.
  2. Turn the flash to pass switch ON and OFF.

Does the headlamp flash to pass function operate properly?

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

Go to Step 3

3

Do the high beam headlamps operate properly?

Go to Step 4

Go to Headlamps Inoperative - High Beams

4

  1. Turn OFF the ignition.
  2. Install a scan tool.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Flash to Pass Switch parameter in the dash integration module (DIM) Inputs data list.
  5. Turn the flash to pass switch ON and OFF.

Does the flash to pass switch input parameter turn ON and OFF with the switch?

Go to Step 5

Go to Step 6

5

With a scan tool, command the High Beam Relay ON and OFF from the DIM output control data list.

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

Go to Step 11

Go to Step 7

6

  1. Turn OFF the ignition.
  2. Disconnect the turn signal/multifunction switch.
  3. Connect a 3-amp fused jumper between the flash to pass switch signal circuit of the turn signal/multifunction switch and the ground circuit of the turn signal/multifunction switch.
  4. Turn ON the ignition, with the engine OFF.

Does the flash to pass switch input data parameter display ON?

Go to Step 10

Go to Step 8

7

Test for an open 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 11

8

Test the turn signal/multifunction 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?

Go to Step 14

Go to Step 9

9

Test the flash to pass switch signal 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 14

Go to Step 11

10

Inspect for poor connection at the turn signal/multifunctional switch assembly. 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

11

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

12

Replace the turn signal/multifunction switch assembly. 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

Important:: Perform the setup procedure for the DIM after DIM replacement. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

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

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