GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

Connector End View Reference: Lighting Systems Connector End Views or Data Communication Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 

Go to Diagnostic System Check - Vehicle

2

Verify that the turn signal lamps and/or indicators are always ON or flashing.

Do the turn signal lamps operate normally?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Inspect the affected bulb/socket for an internal short, poor terminal contact, or a shorted filament.

Was a problem found?

Go to Step 8

Go to Step 4

4

Disconnect the multifunction turn signal switch.

Do the affected turn signals and indicators still illuminate?

Go to Step 5

Go to Step 6

5

Test for a high resistance or short to ground in the turn signal switch signal circuit.

Did you find and correct the condition?

Go to Step 11

Go to Step 7

6

Inspect for poor connections at the multifunction turn signal switch. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 11

Go to Step 9

7

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

Did you find and correct the condition?

Go to Step 11

Go to Step 10

8

Replace or repair the affected bulb/socket. Refer to Daytime Running Lamp Bulb Replacement or Tail Lamp Bulb Replacement .

Did you complete the repair?

Go to Step 11

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9

Replace the turn signal/multifunction switch. Refer to Turn Signal Multifunction Switch Replacement .

Did you complete the repair?

Go to Step 11

--

10

Replace the BCM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the repair?

Go to Step 11

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11

  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