GM Service Manual Online
For 1990-2009 cars only

Object Number: 613774  Size: MF
Park/Turn Signal, Cornering and Side Marker Lamps
Park/Turn Signal, Cornering and Side Marker Lamps
Handling ESD Sensitive Parts Notice
Lighting Systems Components
Park/Turn Signal, Cornering and Side Marker Lamps

Circuit Description

The Body Control Module (BCM) controls the RF turn signal lamp. The BCM applies power to the RF turn signal lamp which in turns energizes the turn lamp.

Conditions for Running the DTC

The BCM must be commanding the RF turn signal lamp on.

Conditions for Setting the DTC

    • The BCM detects a short to battery in the RF turn signal lamp circuit.
    • The condition above must be present for more than 0.3 seconds.

Action Taken When the DTC Sets

    • The BCM stores DTC B2608 in memory.
    • The SERVICE VEHICLE SOON telltale illuminates.

Conditions for Clearing the DTC

    • A current DTC B2608 will clear if the BCM no longer detects a short to battery in LF turn signal lamp control circuit.
    • A history DTC B2608 will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.

Diagnostic Aids

    • If the DTC B2608 is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections .
    • The following conditions may cause an intermittent malfunction to occur:
       - An intermittent short to battery in the RF turn signal lamp control circuit
       - The BCM is intermittently shorted to battery internally

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. Tests for voltage at the turn signal lamp.

  2. Verifies that the Body Control Module is providing B+ to the turn signal lamps.

  3. Tests if ground is constantly being applied to the turn signal lamps B+ feed.

Step

Action

Value(s)

Yes

No

1

Did you perform the Lighting System 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 RF turn signal lamp control ON and OFF.

Does the RF turn signal lamp turn ON and OFF with each command?

--

Go to Diagnostic Aids

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the RF turn signal lamp.
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the RF turn signal lamp feed circuit with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

--

Go to Step 4

Go to Step 10

4

  1. Connect a test lamp between the RF turn signal lamp feed circuit and the LF turn signal ground circuit.
  2. With a scan tool, command the RF turn signal lamp feed circuit ON and OFF .

Does the test lamp turn ON and OFF with each command?

--

Go to Step 8

Go to Step 5

5

Does the test lamp remain illuminated with each command?

--

Go to Step 7

Go to Step 6

6

Test the control circuit of the RF turn signal lamp for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 9

7

Test the control circuit of the RF turn signal lamp for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 9

8

Inspect for poor connections at the RF turn signal lamp. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 11

9

Inspect for poor connections at the harness connector of the Body Control Module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 12

10

Repair the feed circuit of the RF turn signal lamp. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 13

--

11

Replace the RF turn signal lamp. Refer to Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement .

Did you complete the replacement?

--

Go to Step 13

--

12

Important: Perform the set up procedure for the body control module.

Replace the BCM. Refer to Body Control Module Replacement .

Did you complete the replacement?

--

Go to Step 13

--

13

  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