1998 Ford Ranger 6 cyl Two Wheel Drive Automatic 75,000 miles
the door ajar light and dome light have been coming on for a while when I first start off, but has been going out. This happens when the doors are tightly shut. Tonight the dome light stayed on, tried driving around and moving the switch positions - no luck, still on.
Try spraying tri-flow or WD-40 on the door latch mechanism in the door. The sensor is there, and sticks when it needs lubricated. It fixed the problem in my daughters 96 Ranger. This can be done without dissassembly. Good luck.