90 bronco, right side brake light goes out every once in awhile. tail light works though. changed bulb. i would think bad plug but tail light works (same bulb) even when problem occurs so that plug is ok. its like something with the brakes. then it will work again for awhile. ?

 

I would suspect the lamp socket itself. Had an '86 Parisienne (wagon complete with simulated wood grain sides.....don't ask) with this problem. Replaced the socket after getting tired of pounding on the rear quarter panel to ge the stop/turn filament to flash. Never had the problem come back after that.
Here's another thought. Does it still work when the turn signal is on? If so it may be a contact in the brake switch. The brake switch has seperate contacts for each side so your stop lamps don't back feed and keep your signals from working.

 

were is the brake switch? thats what it seems like it may be..

 

Not 100% certain but most are mounted on the brake pedal assy. somewhere. I would check a manual to be certain. (Haynes, Chilton's, Ford)

 

The brake switch only has one set of contacts, and it's on the brake pedal arm where the MC pushrod connects. It sends power to the turn signal switch in the steering column, where the power is routed to the tail/turn lights. If only one taillight is getting power, then it's a problem in the turn signal switch.

But it's more likely the socket or the wiring along the framerail.

 

thanks for your help. the only thing i noticed about the plug was some oily looking stuff around the out side of it. the truck has been wired for a trailer. theres a place here in tampa called besco auto electric, for 30.00 they will find any shorts or whatever. it just sucks having to drop it off at some place. thanks anyways

 

That oily substance is more then likely No-Ox.......... and anti oxidating compound used on connections or electrical plugs to prevent oxidation of the contacts.