Finally got to drive around a bit in the beast, stopped at the store and on the way out the Jeep wouldn't start. Turns over once then stops, after a few times Then I saw a little smoke coming from under the hood near the PCM.
Noticed 1 of the 3 ground wires connected to the PCM ground stud burned off it's insulation.
So, every time I crank it that ground wire gets super hot.
Sounds like the ground cable to the motor has a problem and the starter is drawing ground thru that small wire. Check the clamp on the battery and connection on the block. The connection on the block is on the drivers side below the exhaust manifold right behind the starter.
If all those wires go to the motor and nothing else is connected into to them in the harness I would say a bad main ground to the motor or body. Did you check the main ground from the battery terminal to body right beside the battery? It's strange only the one wire gets hot in that terminal so see if you can found out where the other 2 go. The factory service manual and Mitchell don't show you much info on those grounds.
Swapped the fuel pump relay and had no issues, replaced it with the original fuel pump relay to make sure that was the issue and it kept working fine. They started it a bunch of times over 2 days then went to move it and had the same issue. Hard to turn over and ground wire heating up... grrrr
You sure your main ground cable from the battery to the engine is fine? Unbolt the cable at the block to be sure it's clean if you didn't already. The starter draws a lot of power when it cranks and if the main ground is bad it with pull ground thru any place it can. Slow cranking is a sign the starter isn't getting the power it needs. If that wire only gets hot when the starter cranks slow I would say your losing ground to the motor and it's trying to pull ground thru that light wire?
Take a multimeter and put it on the voltage setting and put one wire on the engine and the other to the ground post on the battery. Check what the voltage is when it's cranking slow. If you are showing more than .5 of a volt you have an issue with the cable or a bad connection on a terminal.
Turns out the main cable from the battery to the block did have an issue, from my understanding it was checked already but this time they moved it to a different spot on the block and no issues now.
Ok I seem to have the same
Problem as you. I have just changed my starter motor but it hasn’t solved the problem I am still blowing fuses on a random basis. I noticed that exhaust ground wire to frame had come off and wondered if this would cause the problem