Lighting Problem...

[78cj5frankenjeep]

Alrighty guys and girls, I need some help trouble-shooting a lighting problem I’m having. Here it is:

The local Police Department stopped me one evening to let me know that I had no rear lights (on my 78 CJ5 ). My headlights were on, and the brake lights work when the brake pedal is pushed, just no rear running lights. So I get home and check the fuses, and have a blown fuse. I replace this fuse and voila! Rear running lights! But this is where my problems start (or continue)...

Now I have no turn signals. And when I push the brake pedal, the front running lights/turn signals light up in conjunction with the rear brake lights. I can hear the turn signal relay clicking, but the lights themselves aren’t working. I’ve retraced the wiring as it comes out of the steering column and into the fuse panel, and it all looks right (but I don't know if it truly is; I'm not electrical-smart).

Since it's also in the steering column, I should also mention that my horn is disconnected because it blows without the button being pushed when the wires are connected. And if I do push the horn button, I hear a ‘popping/clicking’ sound in the radio speakers…

Ideas? Any help will be greatly, greatly appreciated!

 

[mylittlecj5]

Hmm.. I'd start by checking that the rear wiring harness/light assemblies aren't shorting to ground somewhere. That could be why the fuse blew out, and why the front lights are coming on with the brake lights.

 

[Old Dog]

I'm with mylittlecj, most lighting problems are ground related.

 

[BusaDave9]

This is a good puzzle.
I think it's a short. Not to ground but between 2 signals.

And when I push the brake pedal, the front running lights/turn signals light up in conjunction with the rear brake lights. I can hear the turn signal relay clicking,

If you have ever tapped off the tail lights to wire up trailer lights you know the brake lights share the same wires and bulbs as the turn signals. Here is the rear light wiring:

• White - Ground
• Brown - Running (tail) lights
• Yellow - Left turn/brake light
• Green - Right turn/brake light

Since the brakes affect the turn signals one possibility is a short in the tail light housing. Is there a connector at the tail lights that you could disconnect? With the tail lights disconnected do all the other lights work?
It also sounds like it could be a short in the steering column. After you eliminate the tail lights look for chaffed wires in the steering column.

What fuse was blown? That would be a good clue.

I bet if Click and Clack or someone else much smarter than me were to read your post they could say right away what is causing your problem.

 

[IOPort51]

the horn sounds as if the PO bypassed the horn relay or the relay is stuck, I would guess the static on the radio is the contact / coil making a circuit.
I realy wish I were there, wiring problems are something I enjoy. I know it's kind of sick and weird but I find it challenging and except for contorting under the dash, fun.

The two most important tools needed to work on a CJ are a good electrical diagram and a good volt ohm meter.
The biggest frustration of this site is electrical problems. We really can't do much more than suggest what to look at, try to describe how to find what to look at and offer encouragement.

 

[78cj5frankenjeep]

Thanks guys - I got up early Sunday morning and started working on the Jeep; my lighting problem is now fixed! I don't know what solved it specifically, as I'm not a contortionist fan (for you, IO)... meaning I just took the whole dang dash off and cleaned up the rat's nest of wires up/back there.

I still have the horn problem, though. But now I can at least drive around town (I don't need a horn for that!)... I guess I'll work more on it when the winter comes and I tear out the old interior and put in a new one...

Thanks again