1967 mustang coupe head light and brake light issues
I own a 1967 mustang coupe that I am restoring, I recently put all of the lights back in the car except for the back up lights in the rear valance. I have two issues. One, when i turn the headlights on dim only the passenger side light works, but on brights however both headlights work. Two, when the headlights are on both dims and brights I have no running nor pedal activated brake lights, but the turn signals still work. Any Ideas?
i know that new wire harnesses aren't cheap so rough up the connectors at the rear of the head lamps. one of mine was dim as well and all i did was rough up the prongs with sand paper, and it seems to help
The headlights aren't dim though. They work fine as long as they are on brights, but in normal headlight operation only the passenger side works. Do you still think roughing up the the connections will help?
I would start at the bad headlight and go back.
There should be two filaments in that headlight, remove the bulb and there should be 3 prongs on the back, unplug from the harness from the bad bulb (no low beam) and take a test light and ground it well to the car then with the headlights on low poke your tester in each socket, two of them should light up the test light. The 3rd will be the ground socket on the plug (I think the - is the horizontal one and the + are the 2 vertical ones).
If the test light lights up on two of the prongs your bulb probably has a bad filament for the low beam. You can rig test wires and ground the one that matches the grounding plug on your harness then touch a hot +12V wire to each of the + light prongs to see if they both light high and low individually.
Or you can swap headlights left to right and see if the same bulb doesn't work on low first. Eliminate the cheapest answer first.
HTH, Jon
So the head light issue turned out to be a wire that wasn't making connection. I didn't know until I took the head light out and the brittle wire broke so I striped a new wire and rigged it to see if that was the problem turns out it was. I still have the issue of no running or pedal activated brake lights. I sill have turn signals though. Answers please!!!
Ok, onto issue #2, I have a '67 Coupe also so I tested it.
When you say no running lights do you mean front or rear or both with the headlights on?
The front will only be on with the headlight switch on the first indent (headlights not on but dash and running lights on). With the headlight switch all the way on the front running lights go off because they are only one filament bulbs and become your blinkers with the headlights on.
Your rear should still have running lights as they are dual filament bulbs so they are running lights and the bright filament is either the brake light or turn signal depending on which you're using at the time. I wasn't fast enough to see if the blinker went off when I pressed the brake pedal....
#3 no brake lights- first I would suspect the brake light switch, it's mounted up under the dash at the back of the brake pedal arm and has a little button that when depressed by the pedal closes a contact that activates the brake light. See if the pedal is depressing the switch first then use your test light on it again to see if there is power to the switch first then if power continues through the switch when pressed. The switch unplugs so you can test that plug first, the switch is cheap to replace and you can get it next day usually if they don't have it in stock at most parts stores.
HTH Jon
BY running lights I mean brake lights. With the headlight switch on the first indent, and all the way on there are no running brake lights. The headlights operate fine now. I think I have a bad headlight switch however, because when I pull the headlight switch to the first indent I have no interior dash lights or running lights (front back up lights/ turn signals) Do you think a bad headlight switch could be causing the "No running brake light" issue?
Hi, first lets seperate terms so I can follow,
1. Brake lights would be when you put your foot on the brake pedal,
2. Running lights is when the headlight switch is all the way out, the rear 'running lights' should be on w/o brake lights.
Is it your Brake lights that aren't working or your rear running lights or both?
Do your front running lights light with the headlight switch on the first indent?
I also had no dash lights but found a P.O. had cut the harness near the radio looking for a + connection and never reattached the wire. I wouldn't suspect the headlight switch yet, usually they are all or nothing, they'll get hot and your headlights will go off, switch cools off and they come back on for 30 secs. then go off again, etc. I would more suspect a bad wire.
You're lucky if your turnsignals work, mine still don't and I'm still chasing wires...
Jon
My brake lights aren't working, but I also do not have night time running lights (the red tail lights that run all the time when the headlight switch is on all the way and get brighter when you press the brake pedal). With the headlight switch on the first indent nothing comes on, no running lights, dash lights, etc...When the switch is on all the way The head lights come on, but nothing else does. My turn signals still work though. As you can tell I know nothing about wiring, so any suggestion are greatly appreciated.
You may want to pick up a wiring schematic book for the the '67, it may help if you can follow wiring and aren't color blind like me. I think they're <$15 for the book but most of it is identical in my Haynes shop manual but covers more years.
The brake lights don't have anything to do with the headlight switch as far as i can tell, again i would start at your brake light switch attached to the brake pedal and see if you've got juice at the switch connector first, you only need a cheap <$5 test light.
As far as the dash lights, running lights frt. and rear those could be due to a bad headlight switch, the switch is ~$15 at the parts store if you want to change it for peace of mind and to eliminate it from the equation. I have a feeling that if you remove your steering wheel (use some type of wheel removing tool as the original wheel will break if rocked to get it off) and remove the gauge dash you'll find some cut wires as I did.
After disconnecting my dash I tested the dash lights seperately to make sure it was good and worked backwards from there.
You can also check which fuses power your taillights, etc. to make sure you're getting power from the fuse block first.
HTH Jon
I changed the headlight switch today and all running lights function properly now. I still don't have interior lights. I changed the brake light switch, but I still don't have brake lights. Do you know where the brake light wires run to? and the interior lights?
Ok, now we're getting somewhere. I checked my book and I was incorrect, the brake lights are wired through the headlight switch, there is a 15amp circuit breaker built into the headlight switch controlling:tail lights, stop lights, license lights, parking lights and horns. So since you changed the HL switch that eliminates that.
Did you test the plug going to the brake light switch when you changed it to see if there was juice at the switch? We need to know if it's getting to the switch first. Next I would go to the trunk and pop the stop light bulb sockets out and use the test light on the sockets to see if any juice is getting to the brake light bulbs (someones got to press the brakes), obviously you are getting juice to the running lights, they're working. It could be a bad contact (there are two in the socket) or a bad ground or a bad bulb, it has two filaments, one for running lights and one for brake, one can burn out.
On the interior lights, it says they are fused off of the 7.5 amp fuse in the fuseblock marked '7.5A DOME'. See if anything else that runs off of this fuse is working:trunk light, clock, underdash courtesy lights, dome light, glove box light. You may not have some of these options but see if ANY of these lights are working, if not I would suspect the fuse, you can also test it with a test light, both sides-ones always hot, the other is hot when the light is on that it powers.
If the fuse is good (I'd replace it if you don't get juice to the other side of the fuse clips) sometimes the clips get bent away and don't make good contact also, try pinching them in a little with the fuse out. Does turning the headlight switch all the way left click them on? You may have a bad grounding wire but I can't tell in the book where that is for these lights.
Are all the bulbs good?
Let me know what these tests show.
Jon
So I Started jaking with the stoplight switch connections and finally got the brake lights to work!!! I haven't got around to the interior lights yet, but I'll let you know how that go's
1967 mustang coupe head light and brake light issues 
. I didn't know until I took the head light out and the brittle wire broke so I striped a new wire and rigged it to see if that was the problem turns out it was. I still have the issue of no running or pedal activated brake lights. I sill have turn signals though. Answers please!!!
I haven't got around to the interior lights yet, but I'll let you know how that go's
