Before I state this I have searched for about two weeks trying to figure this out and I'm still lost. I have a 98 f150. Done light will not shut off. Bought truck a month ago. All interior lights we're taken out bought some for the dome light. We'll it does not go off. I have no door ajar light on dash. (Yes it does work) so took light back out. So I decided to see if there we're cabin lights in my third brake light. I did not. Because they we're all melted together. So put dome light back in. Shut doors. Light still on. Clipped melted harnesses in third brake light. Some light goes off. Hey fixed. Open door, on closed door, off. Great I got it. We'll it rained yesterday. Now it's back on. So took dome light out playing around with the screws that power it. Got it to work after a lot of screwing and unscrewing. Then I noticed it was started staying on again bout 20 secs later. But this time it was dim and then it got brighter then back dim, and completely off and back dim then bright. So now it's back on bright and I am lost. Any ideas

 

Bwalk, welcome to the forum!

I deleted the other thread you started on this subject since duplicate posts on a common subject lead to confusing responses that could delay your troubleshooting. Since your problem is electrical, I've left the one you posted here.

Your truck is old enough that I would look for damaged wiring that is in the dome light circuit. It is also possible that the door open switch in one of the doors is not closing properly. This HAS been a problem in older trucks as I recall. Until you find the problem, you could simply remove the bulb.

- Jack