Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnostic Test
- INTERMITTENT CONDITION
- Turn the ignition on.
- With the scan tool, erase all FCM DTCs.
- Turn the HID Headlamps on.
- With the scan tool, read the DTCs.
Does the scan tool display DTC B2807-HID HEADLAMP CONTROL CIRCUIT OPEN?
Yes
- Go to step 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. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
- CHECK THE HID HEADLAMPS RELAY
- Turn the ignition off.
- Substitute the HID Headlamps Relay with a known good relay.
- Turn the ignition on.
- Turn the HID Headlamps on.
Do the HID Headlamps operate correctly?
Yes
- Replace the HID Headlamps Relay.
- Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
No
- Go to step 3
- CHECK THE (L44) RIGHT LOW BEAM CONTROL CIRCUIT FOR AN OPEN
- Turn the ignition off.
- Disconnect the FCM C2 harness connector.
- Remove the HID Headlamps Relay.
- Measure the resistance of the (L44) Right Low Beam Control circuit between the FCM C2 harness connector and the HID Headlamps Relay.
Is the resistance below 5.0 Ohms?
Yes
- Go to step 4
No
- Repair the open in the (L44) Right Low Beam Control circuit.
- Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
- CHECK THE (L44) RIGHT LOW BEAM CONTROL CIRCUIT FOR A SHORT TO VOLTAGE
- Turn the ignition on.
- Measure the voltage between ground and the (L44) Right Low Beam Control circuit at the HID Headlamps Relay.
Is any voltage present?
Yes
- Repair the short to voltage on the (L44) Right Low Beam Control circuit.
- Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
No
- Replace the FCM in accordance with the Service Information.
- Perform the BODY VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Front Control (FCM) - Standard Procedure .
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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