• Hello Guest, we are proud to now have our Wiki online that is completely compiled and written by our members. Feel free to browse our Jeep-CJ Wiki or click on any orange keyword when looking at posts in the forum.

Brake Lights

Brake Lights

GA76cj7

Jeeper
Posts
17
Thanks
0
Location
Guyton, Georgia
Vehicle(s)
76 Cj 7 Levi edition
258 inline 6 stock carb
T18 trans with dana 20
Hi I find myself with no brake lights. First i checked and replaced fuse although it was good. I then thought it could be the switch. I checked power and I Have power going to it and then replaced the switch. but the brake lights still do not come on? The bulbs work when flasher and turn signal is on. I am now coming to you guys maybe you have had a problem like this?
 
When did this start to happen? Have you done any recent wiring mods??
Brake lights are routed through the turn signal switch.
You should have power(12vdc)on one side of the brake pedal switch.
Press the brake pedal, and see if you now have power to the other side of the switch.
Do you have 4-way flashers?
LG
 
No I have not done any mods.I keep the jeep in my garage and needed to take it to go get my gas containers filled for the summer grass season and noticed when I put my foot on the brake I didnt see any lights on the back wall. thats when I stared searching for the problem. I do have four way flashers
 
Last edited:
Please clarify-When you say 'switch'. Do you mean the brake pedal switch that activates the brake lights??
LG
 
I just checked the switch when I press the button in the power shuts off as it should and the other side has power all the time.
 
I just checked the switch when I press the button in the power shuts off as it should and the other side has power all the time.

Your going to have to 'chase' the wiring.
Make sure each tail light has a good ground. Bad ground, is a common tail light issue.
Ck all of your body grounds and be sure they are clean and well connected.
LG
 
Lg is correct on that it goes through the turn signal switch (power from fuse box to brake switch to turn signal switch. Then it goes through Lt green wire and Lt green with black stripe wire to tail lights. If you have a ground for turn signal and hazards then you have a good enough ground to at least light the brake bulb (same bulb as parking and turn signal). If you have a test light (hopefully the style that looks like a ice pick) I would go the the brake switch and check on the turn signal side for power. Then check the wire where it goes into the steering column (behind dash). Then check on column side of plug (in case of corrosion in plug. If you have power to this point then check the Lt green wire (with or without black stripe). If you don't have power at the Lt green wire then you may have a break in the turn signal harness in the column or the switch could be bad. All these tests are down with the brake petal pushed (Brake switch button fully out). I have my notes on when I did the test on the turn signal at my shop. I could give more info with them and the schematic (which is also at the shop, I only have a copy at home.
 
Also-Let me add this. Work your turn signal level up and down a couple dozen times.
This action cleans the contacts within the TS, and can/may restore the brake light operation.
LG
 
Lg good thought. I even thought of pulling on the turn signal harness a little in case of a break (after I walked away from the computer).
 
It looks like I will have to test the harness under the dash maybe even up into the steering column. I do have power at the brake switch but not coming out from under the dash. I ran out of time after cleaning the grounds then checking. finally got my ice pick tester out found out that I don't have power coming out from the dash. If I do have to go into the steering column what will I be looking for?
 
Check the wire from the brake switch (follow it to the plug at the column). Check the wire right before the plug then after. If you have power through the plug and no power on the Lt green wire (column side of the plug) then the problem is the wire harness inside the column or the turn signal switch. If that is the case take a pc of wood and use it to keep the brake petal pushed. Then try flipping the turn signal lever, turn the steering wheel, if a tilt column adjust the wheel , tug on the harness where the plug is. you want to see if you can make the connection (by accident) and make the brake light come on. If it does, you know you will have to pull the wheel to get to the switch to find the problem. If you have power at the column side going in and no power coming out the problem is probably in the column with the turn signal switch/wiring harness.
 
Here's some pics of the plug. The pic with my hand in a glove shows the brake switch plug, pink wire is from brake plug to plug of turn signal switch harness. You can see how it all goes together and trace how the wire goes into the harness. This harness is a painless, colors may be different, but wired the same.
 
Hello all. I am new to the cj community and there is SO much info and most of it is beyond my knowledge. But here goes:1984 CJ7
Driver rear lights do not work at all. Passenger rear lights do but appear as if brakes always engaged-no hazard/turn signals on either side. I have replaced bulbs. I have read the forums on this but do not know where to start- guessing ground issue on the passenger side rear? Do I take the light housing off to find these wires? I am not a mechanic but looks like I will become one- thanks for the help !
 
Welcome to the forum! :ww:

It's possible you have a couple things going on at the same time here.

The brake lights staying on may be the little plunger switch under the dash. Adjustable, but hard to get your hands in there to adjust. If there is free play in the brake pedal, try pulling back (up) on it and holding it with a bungee or something so you can check. Sometimes those plunger switches just come loose from their mounting and this would leave the brake lights on too. Sometimes you just have to replace the plunger switch.

These jeeps use the body/frame as a ground, which causes a lot of problems. Make sure you know what each wire's function is regardless of color - colors fade and change over time.

For testing the lights: take the bulb out, turn the lights on, use a voltmeter and measure between the bulb mount side and the little nubs inside. If no voltage, then run a ground wire (clip leads are fine) from your battery ground or engine block ground back to the metal bulb mount side and repeat. If you have correct voltage then run a ground wire, (I used a #12) from the battery ground back to the rear lights and connected it with a ring terminal to the metal plate in the rear light that the light socket is mounted to. There is a bolt hole in this plate that is used to pick up the ground from the body. I also test the light bulbs before installing them - they may look fine, but sometimes still are bad.

If none of this works, then maybe it's time to run all new wires from the dash back and include a ground. If you replace the light fixture, test the wires, so you know what each one does before you install it.

I did this last year with our '79 CJ7 and it solved the light issues. Also beware, you must go by wire function and not just wire color as some aftermarket lights don't use the same color scheme. 0urs has the same color wires coming from each pigtail in both rear lights, but the wires have different functions. When I ran the new wires I connected them with heat shrink spade terminals, so they could be disconnected if I replace the fixtures or need to remove for other repairs. I also labeled each one with white electrical tape and a sharpie, when I was sure of function.

This may sound like a lot, but if you know how to use a voltmeter you can do this! It just takes a little time. I made a lot of tests and made my own drawings for each circuit to keep track of everything. Good luck and I hope this helps. :D
 
Here's a good place to get a color diagram that will assist you with your learning curve: Jeep 1984 CJ-5 & CJ-7 | Prospero's Garage
I got one of these for our 79 CJ7 . Nice drawing, all laminated, but the seller must have rolled it for shipping tube while it was still warm from laminating it. I cannot read it unless I place it under a heavy piece of glass to keep it from rolling back up. It was a waste of 20$ for me sorry to say.… I found a drawing on the full size jeep site, enlarged it, poster printed and taped together. That's what I work from. Maybe I should contact the guy and let him know what he sent me.
 
I've got 2 of them and they both came out good. If I were you I would contact the guy (politely). I would believe he would work it out. At the least have you send it back and he would send you another.
 
I've got 2 of them and they both came out good. If I were you I would contact the guy (politely). I would believe he would work it out. At the least have you send it back and he would send you another.
Thanks jammer1, I should at least try to contact him. Many folks have been happy with what this guy sells.

BTW you posted some great pics earlier in this thread, and I those have helped me along the way.
 
Wow- great information. I used a voltmeter and checked the light housing in both tail lights and both seem to be getting the correct voltage. I was able to find a rigged connector from the previous owner and now there is continuity to the tail lights but when the brake is pushed the reverse lights come on and the turn signals still don't work. Gggrrrr So I am going to try running a new ground to each tail light and see if that fixes it. The grounds seem to be piggybacked. Do I run a separate ground to each taillight? I will check the plunger switch too.

Your replies are so knowledgable and I cannot thank you enough. I want to be driving this thing!


Sent from my iPhone using Tapatalk
 

Jeep-CJ Donation Drive

Help support Jeep-CJ.com by making a contribution.

Help support Jeep-CJ.com by making a contribution.
Goal
$200.00
Earned
$0.00
This donation drive ends in
0 hours, 0 minutes, 0 seconds
  0.0%
Back
Top Bottom