99 Cherokee sport 4.0 my troubles started a few weeks ago when I went to start my jeep as soon as I turned the key I herd my electronic locks actuate like I hit the unlock button and it wouldn't turn over. It would crank but not turn. I quickly realized if I gave it gas it would start but not idle without my foot on the gas. after taking it around the block about 5 min it returned to normal shut it down and it started right back up no problem. I hoped this was a one time thing it wasn't it happens every few days more so when it is wet out. A few days later I was sitting at a light and my turn signal stopped blinking and went solid same as indicator light on dash. Turned off signal and back on got a few blinks then same thing this problem comes and goes. Now it has evolved I was cruising down the road cruse controll on doin 50 and dash lights started blinking gauges went wild the engine revved and died. I pulled over and same as before it cranked but didn't fire only this time giving it gas didn't work. I sat for about 5 mins and tried it again started up went on my way this keeps happening not always with cruse on sometimes I can throw it in N and restart without stopping sometimes I have to wait. I have no idea where to start any suggestions? Thanks

 

You're in a world of hurt.

 

I had a Bonneville SSEi like that. Doors would lock and unlock themselves, windows rolled themselves up and down, engine killed at random. Wife thought it was possessed and wouldnt' get in anymore.
BCM was shot. Problem is you don't have one.
Check every ground you can get your hands on, chassis, engine, every electrical connector you can find and start shaking wiring harnesses.
Do you have an aftermarket alarm or remote starter? I bet you do. It needs to go.

 

Start with the fuse box in the passenger kick panel. I think there is a wiring harness that comes through the firewall next to the blower motor and inside there are two connectors. Make sure they are seated good and check for any signs of water. Corrosion here can cause all sorts of problems.
Then check the fuse box under the hood and the ECM, same thing- look for loose connectors any water damage.

 

No aftermarket anything. She's as stock as stock gets.

 

Just got through a weird electrical thing like this. What seems to be like the best things to do is 1. Check all fuses 2. Check and clean all grounds especially the big ones (apparently Cherokees are really sensitive to poor grounds) and 3. Check for broken wires in the door boots and that everything is plugged in.

This sounds like a poor ground. Just follow the black wire from the battery you'll find the first two, check the one from the engine block to the firewall (braided silver one) and one that got me was in the trunk there's a bunch of wiring on the drivers side behind the panel where the spare tire goes. Good luck.

 

Thank you for the wonderful advice I found 1 problem with my grounds it fixed some of my problems but not all I'm looking into sensors now when I finish I'll post my fix so if anyone else has similar problems they have somewhere to start thanks again