need some help on my 1980 CJ5 - drivers side brake/turn signal not working

[Papa B]

I need a little help on my CJ5 (AMC 258 i6 / 4.2l ) I just noticed the rear drivers turn signal and brake light are not working - not sure if they ever did as I just bought my CJ last month.

I was just finishing up on replacing the sending unit when I noticed it.
--> the ground common to the sending unit shouldnt have anything to do with the brake lights correct ??

the only difference I can make out is the left side maker isnt there any more - obviously it was left out of the sheet metal repair on the back. But the blue/black wires were still there not term'd






I have

• removed the blue/black wires for the side marker
• replaced the t/s fuse under the dash
• checked the turnsignal bulb and swapped with the pas. side
• attempted to re-ground the assembly - as well as run a seperate ground.
• checked my white / grn / white - black wires from drivers side to the opposite.
• I have also removed the side maker (and wires) from the pas. side.

I dont want to mess with the column as i dont have a wheel puller so Im hoping its not the swithc in the column.

 

[Torxhead]

Since you have swapped out the rear taillights with no success, the next thing to check would be the light socket for any voltage going to it. From there the tailight wiring goes to the directional/hazard switch. The turn signal flasher might come into play here so check that. The tailights are grounded to the body, which the body is grounded to the battery from a ground cable located right behind the battery negative post, or it should be.

 

[Papa B]

well... that was easy thanks Torx you hit that nail on the head...

never thought to check the ground at the battery,
- raised the hood
- saw the brand new battery and cables
- ran the old ground cable over and term'd
- vwalla

now i gotta run to the store and get a new bulb... as many times as I handled those two bulbs today - it was bound to happen, I fumbled one and watched it splatter into a few 100 pcs...

 

[Torxhead]

So help me out here, you hook up one measly negative cable and everything works?

 

[mtnwhlr]

 

[Tommy986s]

Im having a problem with the front signals not working, not sure if the problem is related but am interested to hear causes for your problem. I did jump my front signals to the rear to pass inspection, the only problem is they come on when the brakes are pressed.

 

[Papa B]

So help me out here, you hook up one measly negative cable and everything works?

Yeap... with the exception of an intermitant wiper motor. which ill worry about next weekend.....

mind you everything in the rear tail lights/turn signal has been un-jimmy rigged so there may have been a few things which were just elimnated as I chased the problem to the battery per your advice.

 

[Torxhead]

Papa B, it could be another grounding issue, the wiper motor does not have a separate ground wire and is grounded to the windshield frame. I would suggest you run a jumper from the wiper motor housing to the battery negative, since that is the best ground location and try that. Normally the wiper motor grounds itself thru the bolts at the windshield frame and there might be some restriction after 32 years.
Tommy986s, you could have a similiar issue with the light circut not returning to the battery negative thru the body ground.

 

[Tommy986s]

Papa B, it could be another grounding issue, the wiper motor does not have a separate ground wire and is grounded to the windshield frame. I would suggest you run a jumper from the wiper motor housing to the battery negative, since that is the best ground location and try that. Normally the wiper motor grounds itself thru the bolts at the windshield frame and there might be some restriction after 32 years.
Tommy986s, you could have a similiar issue with the light circut not returning to the battery negative thru the body ground.

My problem is that Ive completely disassembled and reassemble the jeep, it has an 84 engine harness and 78 dash harness, that could have something to do with it. Im not getting power from the fuse block to the front lights (signals only) everything else works, I am to the rears, Ive separated the wire harness from the block, cleaned all connections, but at the same time I have no idea if this was a problem before i purchased the jeep, possibly could be a back fuse block, I have checked and even added grounds to the front turn signals, added a heavy duty ground to the body from the engine block. kinda stumped at this point..... At least its legal though annoying.

 

[Torxhead]

So then you could trace back your existing wiring, it has to go somewhere. Finding a wiring schematic could help.

 

[Tommy986s]

I have a Chiltons, time to get a headache.... I hate wiring diagrams.

 

[mscottb]

Just fixed my problem with my 1980 CJ5 . Had the same issue as you but I had an extra problem with a melted wire inside the harness, seems the PO placed a high amp fuse instead of the 5 amp required. walla almost a fire. re run the wire and clean some contacts, redue some grounds and now all the lights work. also the circuit diagrams where a mess to deal with as I had to use 1978 and 1980 diagrams. good luck

 

[Tommy986s]

I appreciate the advise, I had to go with the 84 wiring harness from my parts jeep because the 78 was so butchered and decayed. You are possibly correct as the PO on the 84 had wired in fog-lights and all sorts of other straight to the harness without fuses. Wish there was a place to get a new 78 engine bay harness, I have over 8 packs of wires containing 2-6 wires each sitting under my battery not hooked up to anything and don't know where they go.. not sure if the 84 was FI that might be some of them.

 

[canuckcj5]

hmmm ill have to check the grounds on my cj, i also dont have the drivers side brake light not working either, after doing a body swap thou,