B1008-18
B1008-18-RIGHT TURN LAMP - UNDER CURRENT
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The Body Control Module (BCM) receives an input from the Left Multi-function Switch requesting turn signal lamp illumination. When this message is received, the BCM provides a pulsed voltage output through the Front and Rear Turn Signal Driver circuit. The Turn Signal Driver circuits connect to the single filament Turn Signal Lamps. For additional information on the Turn Signal Lamps operation, Exterior Lamps - Operation.
- When Monitored:
With the turn signal active.
- Set Condition:
When the Body Control Module (BCM) detects less than expected current draw on the Right Turn Signal Driver circuit.
1. CHECK FOR AN ACTIVE DIAGNOSTIC TROUBLE CODE (DTC)
NOTE: Prior to diagnosing this DTC, verify that the correct wattage bulbs are installed.
1. Turn the ignition on.
2. With the scan tool, read DTCs.
Does the scan tool display this DTC as active?
Yes
- Go To 2
No
- Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
- Perform the BODY VERIFICATION TEST. Body Verification Test.
2. CHECK THE (L60) RIGHT FRONT TURN SIGNAL DRIVER CIRCUIT FOR AN OPEN IN THE HARNESS
1. Turn the ignition off.
2. Disconnect the Right Front Park/Turn Lamp harness connector.
3. Disconnect the BCM C1 harness connector.
4. Measure the resistance of the (L60) Right Front Turn Signal Driver circuit between the Right Front Park/Turn Lamp harness connector and the BCM C1 harness connector.
Is the resistance below 5.0 Ohms?
Yes
- Go To 3
No
- Repair the open in the (L60) Right Front Turn Signal Driver circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.
3. CHECK THE (L62) RIGHT REAR TURN SIGNAL DRIVER CIRCUIT FOR AN OPEN IN THE HARNESS
1. Disconnect the Right Rear Park/Turn Lamp harness connector.
2. Disconnect the BCM C2 harness connector.
3. Measure the resistance of the (L62) Right Rear Turn Signal Driver circuit between the Right Rear Park/Turn Lamp harness connector and the BCM C2 harness connector.
Is the resistance below 5.0 Ohms?
Yes
- Go To 4
No
- Repair the open in the (L60) Right Front Turn Signal Driver circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.
4. CHECK THE (Z910) GROUND CIRCUIT FOR AN OPEN IN THE HARNESS
1. Using a 12-volt test light connected to 12-volts, check the (Z910) Ground circuit at the Right Front Park/Turn Lamp harness connector.
Does the test light illuminate brightly?
Yes
- Go To 5
No
- Repair the open in the (Z910) Ground circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.
5. CHECK THE BCM FOR CORRECT OPERATION AT THE RIGHT FRONT TURN SIGNAL
1. Turn the ignition off.
2. Reconnect the BCM C1 and C2 harness connectors.
3. Connect a 12-volt test light between the (L60) Right Front Turn Signal Driver circuit and the (Z910) Ground circuit at the Right Front Park/Turn Lamp harness connector.
4. Turn the ignition on.
5. Turn the Right Turn Signal on.
Does the test light blink on and off?
Yes
- Go To 6
No
- Replace the BCM. Body Control Module - Removal.
- Perform the BODY VERIFICATION TEST. Body Verification Test.
6. CHECK THE BCM FOR CORRECT OPERATION AT THE RIGHT REAR TURN SIGNAL
1. Connect a 12-volt test light between the (L62) Right Rear Turn Signal Driver circuit and the (Z910) Ground circuit at the Right Rear Park/Turn Lamp harness connector.
2. Turn the Right Turn Signal on.
Does the test light blink on and off?
Yes
- Replace the Turn Signal Bulb. Turn Signal Bulb - Removal.
- Perform the BODY VERIFICATION TEST. Body Verification Test.
No
- Replace the BCM. Body Control Module - Removal.
- Perform the BODY VERIFICATION TEST. Body Verification Test.