[Noangel]

While idling, my 1999 Explorer 5.0 headlights and dash lights come on by themselves. When they come on uncommanded, I can’t turn them off. I can get the hi-beams to work. At random the lights will go off and everything works as it should. If I turn the ignition off the lights go off (grateful for that). When they come on uncommanded the rotary switch for lighting does nothing. My assumption is a relay is activating by itself, which one and where it is I can’t tell with my manual. Not a showstopper, in fact this issue could have been present for a while and I am just now noticing it. Anyone else experienced this?

 

[J_C]

So you haven't owned the explorer for long? My first guess is grime or hardened grease on the auto-headlamps slider switch on the windshield, rearview mirror. My '98 periodically does similar to yours. If sliding that full travel left and right a few times doesn't help enough, you might try gently heating it with a hair dryer and then sliding it back and forth again while the old grease is softened up.

 

[Noangel]

I’ve owned it since 2005. However, I haven‘t used it much in recent years. Don’t know that I would have noticed the lights coming on in the daytime while driving. Main reason I noticed it now was because it was in the garage. While I had the hood up working on radiator hose, the lights would come on and then go off by themselves. Will try the slider switch you mentioned. Thanks.

 

[Noangel]

I’ve owned it since 2005. However, I haven‘t used it much in recent years. Don’t know that I would have noticed the lights coming on in the daytime while driving. Main reason I noticed it now was because it was in the garage. While I had the hood up working on radiator hose, the lights would come on and then go off by themselves. Will try the slider switch you mentioned. Thanks.

JC
You were right about that switch. I barely touched it and the lights came on. Even though the slider switch is at the left full stop position. Might try your hair dryer approach next, or I might get really motivated and take the mirror and light assembly apart to fix it the right way. LOL. Hell to the no on the right way remark. I will definitely try the hair dryer first. Thanks for solving my problem!
NoAngel

 

[J_C]

Thanks for completing the topic with the solution. If the hairdryer doesn't work, it could be of benefit to take it apart, including that there may be some oxidation on the slider wipers or they could need more spring tension bent into them.. It's essentially a linear potentiometer.

If it weren't a mirror then I'd suggest spraying contact cleaner into the slot that the knob moves along, but I don't know if that would cause problems for the mirror reflective coating or photochromatic layer. You could probably get a replacement to fiddle with at a junkyard for $15 or so.