GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Exterior Lights Schematics

Connector End View Reference: Component Connector End Views .

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle .

2

  1. Ignition ON.
  2. Activate the left and right turn signals.

Do the turn signals and indicators operating correctly?

Go to Testing for Intermittent Conditions and Poor Connections .

Go to Step 3

3

Is only one lamp inoperative?

Go to Step 4

Go to Step 6

4

Place a test lamp between the supply voltage and ground circuits at the inoperative lamp socket or connector.

Does the test lamp illuminate when the turn signal is activated?

Replace the inoperative turn signal lamp. Refer to the appropriate replacement procedure.

Go to Step 5

5

Test for an open or high resistance in the supply voltage circuit or ground circuit of the inoperative lamp. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

System OK

Go to Step 10

6

With a scan tool, activate each turn signal with the body control module (BCM) output control function.

Do all lamps operate correctly?

Go to Step 8

Go to Step 7

7

Are only the instrument panel (I/P) turn signal indicators inoperative?

Replace the instrument panel cluster (IPC). Refer to Control Module References , for replacement, setup, and programming.

Go to Step 9

8

Test for one of the following conditions. Refer to Circuit Testing and Wiring Repairs .

    • An open, high resistance, or short to voltage in either turn signal switch signal circuit
    • An open or high resistance in the turn signal switch ground circuit

Did you find and correct the condition?

System OK

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

9

Test for an open, high resistance, or short to ground in the supply voltage circuits of the inoperable lamps. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

System OK

Go to Step 10

10

Test for a poor connection at the harness connector at the BCM, driver door switch, or passenger door switch as applicable. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

System OK

Replace the body control module (BCM), driver door switch, or passenger door switch as applicable. Refer to Control Module References , for replacement, setup, and programming.