Why won't my brake lights work?

Today was the beginning of organizing the rats nest of wires in the '67. A PO had run double wires to the tail lights so that was corrected and I put on new taillights since the old ones were a little dry rotted and not grounding very well.

Anyway, the main question is: How to get my brake lights to work? They haven't worked since I got the Jeep so I'm sure it's not my fault (Right?). I put in a new stop light switch (the one on the master cylinder) and I traced the wires that go to it. Both are brown. One goes to the battery pole on the headlight switch and one was just hanging through a hole in the firewall, hooked to nothing. I have the wiring diagram and it said one goes to the turn sig. switch. So I unwrapped 40 feet of electrical tape off the steering column and sure enough there are three wires coming out of the turn signal switch that were cut off and go to nothing. One is brown, so I hooked the lonely brake light wire to it and still no brake lights. The other two coming out of the turn sig switch that go nowhere are a black one and a baby blue one.

Hopefully someone has some guidance. Thanks.

 

I just went through this a few months ago. The P.O. of my rig installed separate circuits for brake lights, turn signals, etc....so when I troubleshot my cut brown & black wires, they led to nazzing. The hardest part was unwrapping the 40 feet of elect. tape, lol.

Here's a link to a color wiring diagram that may help:

http://www.imagestation.com/picture/sraid132/p5aeaaca5311077b630c08aa7e1af0697/f796e204.jpg

I've resized it so that when maximized it should print one one sheet of paper.
Good luck, and get a voltmeter and/or test light if you don't already. That'll help a ton. HTH!
-Alan

 

Thanks for the tips. I got a voltmeter and sure enough, the brake light switch works. The issue must be in the turn signal switch. The color diagrahm is great. I'll be sure to replace my ink cartridge soon so I can print it.

 

madmax, good luck! You can always peer at the diagram on the 'puter in the meantime.

Just be glad you don't have the 4-way hazard lights that come in the 1971 model...those integrate with the turn signals. Blaaahh!!

 

I'd start by turning the ignition on and putting the left turn signal on. Does the rear light flash? Does the front light flash? And if they don't flash, do they at least come on? do the same for the right signal.

If the flashers work and the brake lights don't then it is the set of brown wires that are not working correctly.

Now if you have no lights at all, I'd start by making sure that the brake lights will come on. I'd go as far upstream as I could -- to the wire that comes out of the turn signal switch heading for the rear and apply 12 volts and see if the light comes on.

If I recal correctly the wire colors for the lights will be orange and green with white trace for right and left, respectively.

If you disconnect the orange wire at the turn signal and put 12 volts on it the light should come on. Do the same for the green / white trace. If not then the problem is downstream from the switch.

If that works, then I'd hook it back cup and short the two terminals of the brake switch. The lights ought to come on. If not, then the brown wires are not working.

I suppose the switch could be bad, but since there are two separate circuits going back L and R, that would mean that there had to be two problems in the switch which is possible but duplicate problems happening at the same time are usually not my first choice.

good luck

kamel

 

All four turn signals work. The brake light switch is now working according to the voltmeter. The problem is that when I hook the magic brown wire to the turn signal switch, it does nothing. And there is not an orange wire on the turn signaal switch. Maybe there was supposed to be, but not now. I ordered a new turn sig assembly and I'll post the progress when it comes in.

 

OK, so you are in luck! The 12 volts runs to the brake light switch which is normally open. When you press on the brakes the switch closes and allows the 12 volts to go to the turn signal.

I assume that you tried putting the left and right flasher on and press the brakes then with a similar result.

I also assume that you checked to make sure that the front parking lights are not coming on when the brake is depressed. Don't laugh, I've seen that before on an old 2A that I bought.

So, you ought to be able to read 12 volts on the brown wire that you are trying to hook to the turn switch. Press the brake pedal and you should get 12 volts, release the brake pedal and it should go to zero.

If that is OK, then you ought to be able to reconnect the wire to the turn signal. If you have the turn signal cover off you ought to be able to do the same 12 volt - zero volt test where the brown wire comes into the switch. If that is OK, then maybe the turn signal switch has a problem or there is a bad connection from the brown wire to the terminal on the switch.

On the orange and green/wh tr wire; I took a wiring harness apart that was in a 71 cj5 and those were the colors that were used there to go from the t/s switch to the rear lights.