No brake lights

[bigrigdom]

well my brake lights have stopped working recently and i have no idea what to do. the turn signals and tail lights still work, just not the brake lights or hazard lights. i went to carquest and got what I though was a new brakelight switch that connects to the top of the brake pedal. put it in and no go. so i had a friend come over and check it out, he has quite a bit more experience with this stuff than I do. he looked and said he didnt think what I got was the brakelight switch cuz there was another switch above it on the break pedal that looked more like the switches hes familiar with but it had a vacume hose hooked up to it (no vacume though) and no electrical wires and hes never seen such a thing. we followed the hose into the engine bay and it went into some goofy looking thing and at this point my head is starting to hurt just thinkin about this stuff....can anyone help me? sorry this was so long.
thanks in advance.
dominic

 

[eyoung429]

Sounds like it can be 1 of 2 things.

A cut off switch for cruise control or for an aftermarket tow package brake system.

Since your brake lights and hazzard lights work off the same filament in the bulb, I would guess that either the hazzard relay or the fuse for them is toast.

Take a voltmeter and go from each connection to the brake switch and see if you have power. If you don't, check the aforementioned.

If you do have power to the switch, make sure that the running lights are off and take the bulbs out of the taillight assembly then have a friend tap the brakes and make sure you have power to one of the 2 connections in the base of the light socket. If you have power when the brake pedal is depressed, then put new bulbs in...if you don't have power, then check the connection under the bed and check the wires to make sure that none of them are bare and touching a metal component.

One other thing....have you recently hooked up a trailer to your rig? If so, is this when the problem started occurring? You may also have a short to ground in the pigtail in the trailer connection.

 

[Darrin Tosh]

I keep trying to check mine but by the time I am out of the truck and run to back the lights go off,..Truck's too long I guess,..

 

[towcat]

dom-
I was flying low through your town a couple of nights ago
the switch that your friend found with the vac tube is the shutoff switch for the cruise control kinda goofy how ford done it but it's goof-proof and maintence free.
check the switch at the end of your booster pushrod and make sure one end has 12v going to it. I've found many 80-86's with no voltage there.for starters. I don't have the fuse number for you to trace it down to, but if you do need to field fix it in the meantime, tap into your cig lighter wire and you will be legal again until you have traced the problem.

 

[subway]

dont forget that the brakes run throught the turn signal switch, thats what failed for me on my old truck. the brake lights would actaully work if i held up on the switch but if i let off the turn signal switch the brakes would not work.

thats after i cleaned up all my grounds and replaced the brake switch, check fuses and pulled some hair out.

 

[bigrigdom]

I just want all you guys out there to know that without this forum I would be completely screwed! thanks for the suggestions. after I get off work im gonna start checking it out. im just glad it doesnt have anything to do with that vacume cuz that is way beyond me. thanks again
dom

 

[Darrin Tosh]

Yer welcome I am glad I could help!