I have a '99 F150 4x4, AT with 5.4.

About a week ago I noticed my dome light was staying on. I was in a hurry so I pulled the bulb. I then forgot all about the problem. This morning I got to work and my interior lights (by the doors) and cargo light wouldn't go off.

I finally pulled the #14 fuse and they went off.

Is this the door switches sticking or a relay? It looks like there are two relays that control interior lights. I just thought it could be more of a problem because it started with the dome light and has now moved to other lights on the same circuit.

 

The switch is inside the latch in the door. Spray some WD 40 in to latch assembly then open and shut the door about 20 times.....do both front doors. That should do it.

 

Thanks Spotty,

I'll give it a shot. I actually think you may be right but I really suspect the passenger door is the culprit. Both times it has done this was right after someone was riding with me. I did check that door today when it happened but I only flipped the lever in the rear door. (supercab) Is the switch you are talking about in the front door? What is the toggle lever in the rear doors for?

 

On both of mine I have the extended cab with the suicide type back doors.....the switches are only in the front doors. If you have 4 full size doors, then I don't know if all 4 have the switch. If you open the back doors and the dome light comes on, then yes....all 4 must have the switch.....spray them all down.

 

This just keeps getting weirder.

After pulling fuse #14 yesterday I thought I had at least found a temp solution. But when I left work and then stopped to do an errand, both the interior light and the cargo light came on for awhile. (not sure how long but I stood there for about a minute and then looked out a window when I got inside about 2 minutes total they were still on) When I came out 10 minutes later they were off.

Got home and tried the WD-40 in the door switches and that didn't do anything. At this point both lights had been on for 15 minutes or longer. So I pulled the #15 fuse and they went out. Problem with that was truck would start but wouldn't come out of park. Had to start it in neutral. Couldn't have that so I put the #15 back in. Both lights stayed out at this point but only if I turned off the auto-lamp switch.

This morning I got in, turned on the headlights and drove to work. When I got here the headlights stayed on after I turned the switch off. They have never done that before no matter what I did with the auto-lamp switch. And the dome lamp and cargo light were on too. I turned the auto-lamp switch on and then back off, the headlights went out. At this point the only way the headlights would come on was by turning on the auto-lamp switch. The normal headlight switch did nothing. The dome and cargo lights were still on so I went inside to get my flashlight and needlenose fuse pullers. By the time I got back out to my truck the lights had gone out. So, half an hour later I take one of my buddies out to show him what my truck is doing and everything works like I thought it should. The headlights come on with the switch and the dome and cargo lights didn't come on (fuse is pulled). I didn't want to create any more problems so I didn't put that fuse back in or start the truck.

At this point I think it almost has to be one of those relays or something in the timer for the auto-lamp. I have a Chilton book and an Alldata subscription so maybe I can track down which relay it is and just start throwing parts at it. I sure don't want to leave it in its' current state because eventually I'll be stranded without any lights at all.