For 1990-2009 cars

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 2 | Go to Diagnostic System Check - Vehicle
2 | Verify that the turn signal lamps and/or indicators are inoperative. Do the turn signal lamps and/or indicators operate normally? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3
3 | Are only the turn signal indicators in the instrument panel cluster (IPC) inoperative? | Go to Step 4 | Go to Step 5
4 | Test the inoperative turn signal supply voltage circuit to the IPC for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 7
5 |

1. Place the ignition switch to the ON position with the engine OFF.
2. Using a scan tool, command the left and right turn signals ON and OFF with the BCM special functions scan tool output controls.

Can you activate the turn signals with the scan tool?

Go to Step 6

Go to Step 9

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

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

• | An open or high resistance in the turn signal/multifunction switch ground circuit

Did you find and correct the condition?

Go to Step 13

Go to Step 8

7 | Inspect for poor connections at the IPC. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 13 | Go to Step 10
8 | 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 13 | Go to Step 11
9 | 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 13 | Go to Step 12
10 | Replace the IPC. Refer to Control Module References for replacement, setup, and programming. Did you complete the repair? | Go to Step 13 | --
11 | Replace the turn signal/multifunction switch. Refer to Turn Signal Multifunction Switch Replacement . Did you complete the repair? | Go to Step 13 | --
12 | Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the repair? | Go to Step 13 | --
13 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3