98 for expedition DOOR AJAR light

Good afternoon. I have a 98 ford expedition that has the door ajar light on and dings all the time. It's driving me insane. I hit a small bump and DING and the inside lights come on. All doors are shut. The doors will lock and unlock.

I'm not sure if related but I will mention. The driver side back door sometimes doesn't look when I lock using front drivers door.

I read somewhere to get in the truck and have someone open and shit every door and listen to the one that doesn't ding. They all do.

This light sometimes doesn't come on all day long. Then sometimes it's on front first start of the day and even sometimes it just comes on for the first time that day just riding down the street.

Is there a way I can figure out what door is causing this?

Ford in that time frame had many vehicles that would get the door ajar problem due to dirt in the contacts. Search the forum for ajar and WD40 (or wd-40) and there are plenty of replys on how to spray it into the latch area to clean the contacts to fix the problem. There are a few instance where this doesn't work and the door has to be taken apart and the contacts given a good cleaning by hand or replaced. And there are a few others where it is a wire going bad, usually in the hinge area. It has a break and in different positions makes contact, and in others loses it.