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 Instrument Panel, Gages, and Console Connector End Views in Instrument Panel, Gages, and Console or Power Door Systems Connector End Views in Doors

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

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 in Wiring Systems

Go to Step 3

3

Are only the turn signal indicators in the instrument panel cluster (IPC) always on or flashing?

Go to Step 9

Go to Step 4

4

Are only the turn signal lamps on one side of the vehicle always on or flashing?

Go to Step 5

Go to Step 7

5

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

Was a problem found?

Go to Step 14

Go to Step 6

6

Test the following circuits of the affected lamps for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

    • The left or right turn signal lamp supply voltage
    • The left or right turn flasher signal
    • The left or right turn signal switch signal
    • The left or right trailer stop/turn lamp supply voltage

Did you find and correct the condition?

Go to Step 18

Go to Step 7

7

Disconnect the multifunction turn signal switch.

Do the affected turn signals and indicators still illuminate?

Go to Step  8

Go to Step 10

8

Disconnect the front door module on the same side as the affected lamps.

Do some of the affected turn signal lamps and indicators still illuminate?

Go to Step  11

Go to Step 12

9

Inspect for poor connections at the IPC. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 13

10

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

Did you find and correct the condition?

Go to Step 18

Go to Step 15

11

Inspect for poor connections at the turn/hazard flasher. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 16

12

Inspect for poor connections at the front door module on the same side as the affected lamps. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 18

Go to Step 17

13

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

Did you complete the repair?

Go to Step 18

--

14

Replace or repair the affected bulb/socket.

Did you complete the repair?

Go to Step 18

--

15

Replace the multifunction turn signal switch. Refer to Turn Signal Multifunction Switch Replacement in Steering Wheel and Column.

Did you complete the repair?

Go to Step 18

--

16

Replace the hazard/turn flasher. Refer Hazard and Turn Signal Flasher Replacement .

Did you complete the repair?

Go to Step 18

--

17

Important: Perform the set up procedure for the door module.

Replace the door module for the inoperative outside rear view mirror turn indicator. Refer to Door Lock and Side Window Switch Replacement - Driver Side or Door Lock and Side Window Switch Replacement - Passenger Side in Doors.

Did you complete the repair?

Go to Step 18

--

18

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3