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Electrical Issues

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Electrical Issues
B

Berg

Jeeper
Posts
78
Thanks
0
Location
las cruces, NM
Vehicle(s)
85 cj7 laredo
I found that when I hit bumps in my cj the electrical cuts off then comes right back after a second and the bumps arent even bad! any one have some ideas?
Thanks
 
Everything cuts off? Even the engine? The head lights?

If the head lamps also cut off - since they do not require the ignition to be on - could be about 10000 things... :) Main feed from the battery, main solenoid connection, main ground - I could go on on an on. Your going to start checking all you grounds and feeds.

If the head lights stay on the it is most likely in the switched key circuit... Could also be about 10000 things... :) Again - have to check the obvious then work your way back.
 
Ya its all interior and exterior lights and stereo. The wiring is pretty bad. Not the engine it keeps running.
 
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That is more then weird - if the head lamps go out - your loosing a main feed circuit as they work regardless of the ignition switch position. But, if you loose the main feed your engine should stop... :(

Do you have a manual? Look for the circuit that powers the head lamps (from what you say it will be separate from the ignition) - you should be able to narrow it down from there.

BTW - If you give us a hint as to the year and model - it sure helps one hell of a lot! :laugh:
 
Berg said:
I found that when I hit bumps in my cj the electrical cuts off then comes right back after a second and the bumps arent even bad! any one have some ideas?
Thanks
Click to expand...

Are you talking dash lights? or just interior & exterior?
It could be in the headlight switch it's self.
Also could be wiring insulation rubbed off against the tub causing a dead short.
 
yep, my gauges go to zero (gas,temp,radio etc) when I turn on the heater?????
 
Berg said:
Ya its all interior and exterior lights and stereo. The wiring is pretty bad. Not the engine it keeps running.
Click to expand...
Just for giggles run a groung wire from your battery to your dash and see what happens. It could be a bad ground. If that doesn't help have fun tracing down the problem. The wiring in used cj's is usually a mess, but most problems are ground related.
 
try the bulk head connector on the firewall everything runs through it. It could be loose or full of mud, rust, or some other type of corrosion. i took mine apart and cleaned it with brake parts cleaner and put fresh dielectric grease in it.
here is a write up on how to do it from JP MAGAZINE
Cleaning Electrical Connectors - Jp Magazine
 
I have been an electrician for over 30 years and all I can say about CJ electrical systems is they suck. For such a outdoor based vehicle, (and what that means is one designed to be abused off road) the electrical systems they used were never up to par with the task asked. Early Cjs had no fuse boxes, early and later ones depend to much on chassis grounds that will see dirt and corrosion like no on road based vehicle. I always check grounding and I run extra wire to bring out grounding when I rewire a jeep.
My biggest advice to anyone having electrical problems with a CJ is to chase down your grounds and clean them up. remember electricity runs down the outside of a conductor, and if that is not clean a point of resistance (heat) is created. Also we beat these things up, so connections need to be way secure, loose connections tend to cause intermittent open circuits, and I believe that is what you have.
So clean, protect, and tighten things up and I be the problem will disappear. And if it is something else you il find it as you are following wires around.
 
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Ok well it turns out that were the harness plugs into the firewall the nut that is in the fuse block spins not allowing the screw to hold the main plug together so it was pretty loose. So I cleaned it up and made a bracket to hold it. But I am probably going to need a full engine harness since I keep finding wires broken and brittle. LET THE FUN BEGIN!
 
Definately sounds like a bad ground somewhere. I had a ground to one of my headlights rub against the metal and wore a bad spot on it and would cause my healights and gauges to cut on and off over bumps. Fixed the wire and fixed my problem.
 
Old Dog said:
Just for giggles run a groung wire from your battery to your dash and see what happens. It could be a bad ground. If that doesn't help have fun tracing down the problem. The wiring in used cj's is usually a mess, but most problems are ground related.
Click to expand...

I'm thinking bad body ground, too. It wouldn't have any effect on the running engine, since the engine's grounded directly, but all the dash stuff and all the lights are dependent upon the body ground.
 
Sorry so long for the reply. I just replaced the whole harness with a painless. now I have to add extra heavy grounds to the starter.
Thanks Guys
 
so you rewired, and it works great now. Humm I was sitting down with some popcorn waiting to find out what was wrong with it. I am glad you fixed it but kinda anticlimactic not finding out what the old problem was.
 
It was a mix between bad grounds and the bulkhead connector was not seating together properly, and there was so much electrical tape throughout with bare twisted wires underneath that I needed it to be reliable so new harness was the best way. Sorry I'm always quick to by new things for it.
 
you did good
 
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