GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

1

Did you perform the Lighting System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Turn the ignition switch to the OFF position.
  2. Place the headlamp switch in the HEAD position.
  3. Place the headlamp switch in the OFF position.
  4. Engage the parking brake.
  5. Turn the ignition switch to the ON position.
  6. Place the turn signal switch in the OFF position.

Are any of the turn signal illuminated?

Go to Step 4

Go to Step 3

3

Place the turn signal switch in the RH On position and LH On position.

Do the turn signals operate properly?

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

Go to Step 9

4

Are the turn signal lamps flashing?

Go to Step 10

Go to Step 5

5

Are only the front turn signals illuminated?

Go to Step 6

Go to Step 7

6

Test for a short to voltage in the affected front turn signal supply voltage input circuit 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 12

Go to Step 8

7

Test for a short to voltage in the turn signal supply voltage circuit of the affected rear turn signal. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 10

8

Test for a short to voltage in the affected turn signal switch signal circuit 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 12

Go to Step 11

9

If the turn signals illuminate but do not flash when the turn signal switch is ON, replace the hazard lamp/turn signal lamp flasher. Refer to Hazard and Turn Signal Flasher Replacement .

Did you complete the replacement?

Go to Step 12

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10

Replace the turn signal switch. Refer to Multifunction, Turn Signal, and Hazard Switch Replacement - On Vehicle in Steering Wheel and Column - Tilt.

Did you complete the replacement?

Go to Step 12

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11

Important : Perform the set up procedure for the Body Control Module (BCM). Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

Replace the Body Control Module (BCM). Refer to Body Control Module Replacement in Body Control System.

Did you complete the repair?

Go to Step 12

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12

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2