Sometimes a light on the dash can bug you for a while before you address it. If you know your doors are closed but the door ajar light stays on, you might not care. Follow this Real Fix to see how such an issue was diagnosed and corrected on this 2003 Lincoln Navigator.
Vehicle
2003 Lincoln Navigator 5.4L
Title
B1318, B1566, U1950, Replaced Door Jamb Switch
Complaint
The customer states the door ajar light is on.
Cause
Connected a scan tool and found codes: B1318 – Battery Voltage High/Low; B1566 – Door Circuit Failure and U1950 – UBP Communication Bus Fault. With the ignition on and the engine off, monitored live scan tool data while opening and closing the door and found the door jamb switch parameter was fixed. Performed an inspection of the door jamb switch wiring harness and connector and detected no obvious faults. With the ignition on and the engine off, used a multi-meter to check for the presence of voltage and ground at the door jamb switch and found both were present. Using the multi-meter, checked for continuity of the door jamb switch while operating the switch and found continuity was present in all positions. The results of these tests verified the door jamb switch was faulty.
Correction
Replaced the door jamb switch, cleared codes, performed a road test and verified the vehicle operated properly.