problems with lighting

[dpeebs]

so iv been having this problem for a while now. i was driving to work one day nd when i stopped at work i noticed my voltage was spiking up and down. so later tht night i went home and put my new high output alternator in, it was still doing it after that. iv upgraded all the power and ground wires under the hood. i had a relay for my daytime running lights wired in to pass a safety. but the voltage spikes seem to have to do with my lights, the lights flicker constantly its only the head lights and interior lights, iv checked the brake lights and turn signal lights and license plate lights and they dont do it, iv tried to ask people and nobody seems to know. i was thinking the relay is bad or bad ground or the switch is buggered up on me. can anybody help me out? thanks

 

[RobertFord]

Headlight switch sounds plausible (and is quite a common source for problems). Both the head and interior lights go through it. If it flickers again, try turning the switch itself. Possibly the spring within (acting as a resistor) is fudged up...

 

[Anime]

The headlight switch sounds like the culprit when the headlights and interior lights are flickering. Replace it anyway, it's a safety issue and would go out eventually anyway.

 

[dpeebs]

okay would a 99 explorer switch work in my 91 by any chance?

 

[RobertFord]

No, you need one of these:

http://www.oreillyauto.com/site/c/s...=Explorer&vi=1119608&keyword=headlight+switch