Hey, I just got an 89 jeep cherokee. It didn't start when I bought it but after putting a distributor, coil, and ignition control module in it, it now runs fine. One problem. The black ground wire that goes to the ignition control module is getting very hot and melting things. I replaced it when I put the new ignition control module in because the original wire had burned itself bare. Does anyone know what would be causing the wire to get so hot? I'm worried it will ruin the ignition control module. I used 14 gauge house wire because I was worried the wire wasn't big enough. I can't think of what is causing it. Help!!

 

if the wire came from the factory one size... then that means it would have been fine... are you sure its suppose to be a ground? it could be crossing another open wire somewhere or it is on either end of the wire... like the computer or something...

 

That might be why my jeep cuaght on fire sunday morning. the majority of the damage was in that area. i ifigured it was the igniter that was the cuase fo the problems but you said that your ground wire was melting things. that just might be my culprit.

fortunaltaly i was able to minimize the damage, but still my battery the igniter and the coil pack are toast. literally, as well as one of the hoses that goes to the canister under the radiator hoses and a few wires. mines an 88 btw

 

My bet would be with Huntingman's suggestion that the wire is not supposed to be a ground wire. Have you tried disconnecting it from the block entirely and see what doesn't work? It may be (as he says) supposed to go to the computer control, and if it does rightly go someplace else, you are shorting something out against the block. If it was burned up when you got it, then that may be why you had to replace all those parts to get it running! No telling on buying a used vehicle what some dufus did before you had it! It is unusual for a little 18 gauge wire to bolt as a ground directly from a harness to the block anyway. To run it that way is to risk a fire like Mr. Norris, whether or not that was his problem, which is not worth the risk compared to the time it takes to actually find what that wire is supposed to go to. Somebody out there must have an actual wiring diagram for that harness/plug.

 

Open it up to 8 or 4ga first, cheap test. The smaller the gauge of wire the more resistance, if it is trying to push through more current than its allowed things will get hot. (In simple terms)

 

I tried starting it with the wire disconnected. It would crank but it wouldn't fire, so that makes me pretty sure it is a ground wire. The wire I put in is not touching any others and is connected to the block by a separate bolt(one that is easier to get to). I don't think it is the wire itself that is the problem, I replaced the original only because it was already fried and making no connection. I need to figure out what caused the wire to heat up in the first place.

 

If that wire is a ground, run a second ground wire to the system.
Although there has to be a reason it is drawing such amperage to burn the wire.

 

this and double check all other grounds. battery to block and body. engine to body, if you have a bad or broken ground then the power will seak out the path of least resisitence. if the wire cannot carry the load, it is gonna get hot.

 

x2 that

Good call Throttle

I'm pretty sure most VOM's will do 10A (caution--unfused). He could try putting it inline with this wire and see if the amps change by turning tub accessories on or off, or maybe turning on the key.

Just a thought

 

I just replaced the wire I had with a better insulated one. I then proceeded to check what happens with different electrical systems. I have discovered that the wire only gets hot when the air conditioning is on. When that is turned on, the wire heats up really fast and stops heating up when the air is turned off. Any ideas?

 

Like Throttle said...

Check all your grounds. Sounds like it's seeking ground through a small secondary ground wire rather than large primary ground wire (e.g. tub ground, battery to frame, battery to block, etc)