GM Service Manual Online
For 1990-2009 cars only

Circuit Description

When the body control module (BCM) receives a left turn signal ON command from the turn signal switch the BCM will apply voltage to the left rear stop/turn lamp supply voltage circuit and left turn signal lamps supply voltage circuit. The turn signal flasher is integrated within the BCM and will flash both circuits simultaneously. The turn signal indicator is also illuminated utilizing the left rear stop/turn lamp supply voltage circuit.

Conditions for Running the DTC

The battery voltage must be between 9.0-16.0 volts.

Conditions for Setting the DTC

    • When the BCM receives a left turn signal command and the left rear stop/turn lamp supply voltage circuit is open, shorted to ground, or shorted to voltage.
    • When the BCM receives a left turn signal command and the left turn signal lamps supply voltage circuit is shorted to ground or shorted to voltage.

Action Taken When the DTC Sets

The left front and/or left rear turn signals will not operate or will remain always on.

Conditions for Clearing the MIL/DTC

    • This DTC will clear on current status after the condition for setting the fault is corrected.
    • A history DTC will clear after 100 consecutive ignition cycles without a fault present.
    • History and current DTC(s) can be cleared using a scan tool.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Tests for supply voltage and ground at the inoperative bulb socket.

  2. Tests if battery positive voltage is constantly being applied to the supply voltage circuit.

  3. Tests if a condition exists in the supply voltage circuit.

  4. Tests if a condition exists in the ground circuit.

  5. After replacement of the IPC you must calibrate the new cluster for proper operation.

  6. After replacement of the BCM you must calibrate the new module for proper operation.

Step

Action

Yes

No

Schematic Reference: Fog Lights Schematics

Connector End View Reference: Lighting Systems Connector End Views , Instrument Panel, Gages, and Console Connector End Views in Instrument Panel, Gages, and Console or Body Control System Connector End Views in Body Control System

1

Did you perform the Lighting Systems Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Lighting Systems

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, command the inoperative turn signal ON and OFF.

Does the inoperative turn signal operate ON and OFF with each command?

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

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Remove the inoperative bulb. Refer to Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement , Tail Lamp Assembly and /or Backup, Sidemarker, Stop, Turn Signal Bulb Replacement or Instrument Cluster Replacement in Instrument Panel, Gages, and Console.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp between the ground circuit and the supply voltage circuit of the inoperative bulb socket.
  5. With a scan tool, command the inoperative turn signal ON and OFF.

Does the test lamp illuminate?

Go to Step 4

Go to Step 5

4

Does the test lamp remain illuminated with each command?

Go to Step 7

Go to Step 8

5

Test for a short to ground, open, or high resistance in the supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 6

6

Test for an open or high resistance in the ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 11

7

Test the supply voltage circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 11

8

Does the condition only exist with the turn signal indicator in the instrument panel cluster (IPC)?

Go to Step 9

Go to Step 10

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 15

Go to Step 12

10

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

Did you find and correct the condition?

Go to Step 15

Go to Step 13

11

Inspect for poor connections at the harness connector of the BCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 15

Go to Step 14

12

Important: Perform the setup procedure for the IPC.

Replace the IPC. Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console.

Did you complete the replacement?

Go to Step 15

--

13

Replace the inoperative bulb. Refer To Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement or Tail Lamp Assembly and /or Backup, Sidemarker, Stop, Turn Signal Bulb Replacement .

Did you complete the replacement?

Go to Step 15

--

14

Important: Perform the setup procedure for the body control module (BCM).

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

Did you complete the replacement?

Go to Step 15

--

15

  1. Use the scan tool in order to clear the DTCs .
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK