Newbie needs electrical help

[Jride]

Hi there. First time poster, looking for some help. Have a 1986 CJ7 Laredo that’s giving me some electrical problems.

1. My tail lights keep going out. I keep replacing the 20amp fuse, and it keeps blowing within a day. Doesn’t happen immediately, but usually happens within a day. Where should I start my diagnosis?

2. I’m pretty sure I have something that’s slowly draining the battery. Will jump the car on the weekend. Within 3-4 days I notice the headlights are very dim, and the car won’t turn over. 6-7 days later and there’s zero power left in the battery. So something is pulling juice while the car is off. Where the heck do I begin my search?

Thx in advance for any help!

 

[Manic Mechanic]

First welcome. We love pics around here.

Second as for ur tail light you have a short somewhere. I would start by following the wire back from the light it self and look for a bare spot rubbing the body.

As for the battery that one is a little more difficult as it could be a multitude of things. Most common is a poorly or incorrectly wired aftermarket radio or accessories

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[Jride]

Update:
1. I think I found the culprit for the first issue. There was on old, disconnected wire, hotwired to another. It was in bad shape, melted to a ground wire. I have no idea what this once powered. But the frayed and melted wire would spark every now and then and short the fuse. I’m cut and capped the wire - and hope that will solve it.

2. My lead suspect is a faulty relay. I *think* it’s the horn relay but can’t be sure. The relay is located under the steering column and remains very warm, even when the car has been off for a very long time. This makes me think it’s drawing power from the battery - or something connected to the relay is drawing power from the battery. Think I’m heading in the right direction here?

 

[Manic Mechanic]

Yup

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[Jride]

OK, I'm pretty sure the little box I'm looking at is the horn relay. It has 3 wires, one goes into the steering column, one to the horn (that does not work), and a 3rd that i'm unclear where it leads. (Photos attached).

To test my theory, I removed the top portion of the steering wheel (the part you'd press if you wanted to activate the horn) so that the horn pin is no longer depressed.

The relay is no longer warm when the car is off. So i think that's a good sign, and this may be the problem. The problem is that if i put the steering wheel cover back on, it's going to press the horn pin back in. Haven't quite figured out how to solve this one yet.

Also, attached a pic of my 86. I've owned it since 1997, bought in high school after working three jobs to save up for it. Was kept in storage for 15 years. Just got it back and trying to learn how to fix it myself. Was always petrified to tinker around with it - but recently I've mustered up the courage and I'm starting to to obsess.

 

[TnCJ]

Sounds like you have it figured out and are on the right track.
Welcome to the site BTW. That is a nice looking CJ!!!

 

[JeeperChris]

Here's a diagram from the net for the wheel and horn contacts. The only part I'm not understanding is that I don't see a spring to keep the button off the contact point. I thought I remembered my old '68 Chevelle having a big spring to keep things separated.

https://i.pinimg.com/originals/5e/7a/dc/5e7adc088585d0894555da98d44fbc5c.jpg

This picture names all the parts instead of using part numbers:

http://repairguide.autozone.com/zne...0c152/80/08/ae/7f/medium/0900c1528008ae7f.gif

 

[Impory]

Nice Jeep.....
Did the cj ever have a tow package? May be the remnants of the lights wiring..found something similar on my 86...going through electrical right now...not a fun job..confusing and awkward...lol

 

[Basod]

For the time being just unplug the relay.
If you have meter connect the leads for current and hook one end
To battery negative wire the other to battery neg post.
If it reads current you have a draw somewhere.
Pull the radio harness off as well the yellow constant hot is for memory and clock.

At that point if you still have current start pulling fuses one at a time and monitor for current change. After that you have to trace down whatever leg is causing the ground.

 

[Montanaphilly]

You've got yourself a parasitic drain , you have a hot touching a ground somewhere, could be as small as just a few strands of wires , if your tail light keeps burning out , trace that power wire and see if any of that wire is exposed , or melted to a ground. Or melted to another wire.... or loose wire connections can cause to much current being pulled do to resistance , make sure grounds are tight and wires are tight on connectors etc.

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[Jride]

Montaphilly - that’s exactly what I found. Two old wires, positive and ground, melted together with some threads touching. I removed them.

It’s either that or the horn relay that’s causing the issue. Going to give it a week and see if the battery holds up. I’ll report back.