brake lights out?

[79stang351w]

Previously, I changed headlight switch and all was fine. Then months later, the running lights and brake lights went out. (two days ago) When I jiggled the switch, they came back on. I took out the switch, cleaned everything with crc contact cleaner, emery board and plugged all back in. Still, only the running lights come on. Is there a way to ID the problem wire? Or does my problem lie elsewhere. UGH! Thanks
Mike

[IDMooseMan]

I have an issue with an intermittently working left taillight bulb. It is only one bulb in the taillight. I've traced it down to the wire inserted into the bulb holder itself. Check your bulb holder wires to see if they're loose in the fitting. I taped mine to keep it from moving while driving.

[jadigen]

sure the wires are not broken down by the switch? it was a common problem on these cars. my 90 did it.. th ewires may not look broken but could be inside the casing.

[TWR2003]

Brake light circuit does NOT go thru the headlight switch.

Power goes from the fuse box to the brake light switch (on the brake pedal) to the turn signal switch (in the steering column) and on to the lamps in the rear.

[79stang351w]

OK. The flashers work so it is not the fuse. And, the turn signals work. So, is it the Brake light switch? Thanks for the replies!
Mike

[LilRed86coupe]

Previously, I changed headlight switch and all was fine. Then months later, the running lights and brake lights went out. (two days ago) When I jiggled the switch, they came back on. I took out the switch, cleaned everything with crc contact cleaner, emery board and plugged all back in. Still, only the running lights come on. Is there a way to ID the problem wire? Or does my problem lie elsewhere. UGH! Thanks
Mike

I would just put a new brake light switch on that brake pedal and be done with it. I'm sure that's where your problem is.

[TWR2003]

I would just put a new brake light switch on that brake pedal and be done with it. I'm sure that's where your problem is.

^^^^Umm - youre guessing.

Do yourself a big favor, a bit of work, and $$ for the switch and TEST the circuit first (doesn't cost a penny). Gently disconnect the brake light switch connector from the switch on the pedal. The connector will have two LGRN/RED wires. Put a jumper wire across the two contacts in the connector. If the brake lights come on the problem is in the switch. If they do not come on the problem is somewhere else in the circuit.

[JACook]

Is this on the '79 or the '83? The '79 shares the brake lights with the turn signal function,
but IIRC, the '83 has dedicated rear turn signal bulbs, no? If this is the '79, the brake light
problem could still be in the turn signal switch, even if the turn signals work. But if this is
the '83, then I'd agree this is a problem with the brake light switch.

But.

I wouldn't replace anything without testing it first. It's really easy to tell whether the switch
is working or not. I'll also mention here, if the switch is not working, the problem may be
mechanical rather than electrical.

There must be a small amount of lost motion in the pedal-to-pedal rod pivot, or the brake
light switch won't activate. The master cylinder or brake booster rod works against the
springs in the switch to turn on the brake lights when pedal pressure closes up this clearance.
I have seen several creative interpretations of how the bushings and washers get installed,
that prevented a perfectly good brake light switch from operating. The key here is, no part
of the switch should ever go around the hat-shaped bushing, and the switch should be fairly
easy to rotate, and should snap back to home when you let go.

[79stang351w]

Thanks for the replies! I'll test it. It's the 83.

[jadigen]

check the wiring in the area of that brake light switch.

may be broken in this area,,

[79stang351w]

UPDATE! You guys ROCK! I tested the plug wires, and I got power because the brake lights came on when I jumped it. I bought a new switch, properly installed it, and everything works! Thanks for the help!
Mike

[LilRed86coupe]

UPDATE! You guys ROCK! I tested the plug wires, and I got power because the brake lights came on when I jumped it. I bought a new switch, properly installed it, and everything works! Thanks for the help!
Mike

Congrats!!! I was 99% sure it was the switch. Good job.

[4eyed85gt1]

i have the same problem. i have a failing brake booster. but i have turn signals i have running lights i have hazzards. but no brake lights. i jumped the connector still nothing. fuses look ok. the connector i was spliced before i got it and i cut all the crap out. the red wire was hacked in to the remaining wire. i think the switch is bad, maybe not a good connection. idk. at one point they would work intermittent. now nothing. please help.

[4eyed85gt1]

jumped the two and still nothing. could the wire from fuse block to the switch or even the wire from the switch to the lights be bad, or both for that matter.

[JACook]

..i have turn signals i have running lights i have hazzards. but no brake lights...

The brake lights were shared with the turn signals and hazard flashers on an '82, but they're separate
on an '85. Have you checked the brake light bulbs yet? Sometimes it's the simple stuff that gets ya...

[4eyed85gt1]

i don't have any power to the connector that plugs in to the switch. the bulbs look good but the ends look a little bit on the rough side. and i have power to the fuse for the wiring for the switch. it supposed to go from the fuse box to the switch out to the tail lights. if i looked at the diagram right.

[4eyed85gt1]

sorry if im asking to many questions. i could go buy new bulbs but if i have no power to the brake switch .... yet all other lights work great

[IDMooseMan]

No such thing as too many questions around here. We don't have a monthly limit. Ask all the questions you need, someone will provide an answer.

[wraithracing]

i don't have any power to the connector that plugs in to the switch. the bulbs look good but the ends look a little bit on the rough side. and i have power to the fuse for the wiring for the switch. it supposed to go from the fuse box to the switch out to the tail lights. if i looked at the diagram right.

If you have no power at the switch, then you need to trace the power wire back to the fuse panel and determine why. First I would make sure that you have power on both sides of the fuse. If not, then the fuse is bad even if it looks good. If you do have power on both sides of the fuse, that means that somewhere between the panel and the switch there is a break in the wire. Hopefully you can trace it down and repair it.

As for new bulbs, I am sure they can't hurt, but as you stated if you don't have power to the switch then it won't matter. Just do yourself a favor and check all the little simple things before you make more work for yourself. I have done it to myself many times, so I try to stay in the habit of checking things at least twice before I determine they are good or bad.

Good Luck!

Trey

[4eyed85gt1]

How can one trace the wire back to to fuse box without tearing in to the dash. I did however trace the wires in to another wire loom. But from there i cant get my hands in there to pull away the loom to further trace the problem wire. Does the dash hull need to be removed to further gain more room to access the area of the fuse box. Or can the fuse box be partially removed to get my hand up inside the dash.

[4eyed85gt1]

I did check the fuse block and it has power on one side where the fuse plugs in.

[JACook]

Well, power on one side of a fuse, and not the other == a bad fuse, which would make sense,
since you're not seeing anything on the light green/red wire at the brake light switch. But I'm
confused. You mentioned earlier that the hazard flashers work, and those run off the same
fuse as the stop lights. Am I misreading something?

[4eyed85gt1]

No thats correct im kinda at a loss.

[IDMooseMan]

Post removed by me. Not pertinent to current conversation and troubleshooting session.

[JACook]

OK, so what I do, when things stop making sense, is to go back and verify -everything-
I thought was true or false, from the beginning.

It's possible you have a break in the splice where the circuits for 4-ways and brake lights
join at the back of the fusebox, but that's a very low probability, and it still doesn't explain
the readings you're getting at the fuse, unless you're looking at the wrong fuse.