Have your battery load tested or switch it out with a known good battery. If a cell is intermittantly shorting out or going open circuit. It would act like this. Ive chased one like this and it tested good several times the went dead while I had a meter on it. The main batt + cable connects to everything at the starter (I believe) so check this connecion also (corroded, loose or bad cable)
You said even your radio resets so its loosing all voltage to everything somewhere.
Good Luck

 

I would go back to your starter then you have to start the prosses of elimination somewhere specially with an electrical problem.

 

Ok. In response to the dead cell theory. I replaced the battery with a marine deep cycle. Just for the extra amps. Not working. But I like your thinking. As for the starter. I guess that's what I'm just going to have to do. See this is why I'm a mechanic and not an electrician. With mechanical. Something breaks it's one item that fails leading to other failures. Electricity works on a short comings system. Two or more things can degrade and then look like something else. Stupid Ben Franklin

 

The very same thing is happening to my 90' cherokee, i just made an account here so i could get some answers. One day i noticed her cranking slower and slower then not at all. tried battery charging and jumping her, but no cranking and there was the loss of batter power. so i bought a new battery and terminal ends, again no change. got the starter checked and autozone said it was good. i don't want to believe them though, i tried testing it myself with no luck.
now i can push start her and she will run just fine.
so im thinking it could be the ignition switch or that little rectangular box next to the batter and ign coil with 8 wires going to it.
im new to jeeps but not working on cars, any help would be great. thanks.

 

Yup. Minus the push starting. Sounds just like mine. I'll let you know what I find tomorrow. Aside. I would advise you to keep the account on here. Make it into something. Everyone on here is so nice and the knowledge basin is massive. Besides. We are all jeep heads. What better company to keep

 

Ok. Got under and checked every wire from the starter to the alt to the battery to the circuit box. The inlything shady I can fine is the wire set to the alt. It's been wrapped in electrical tape. I feel this is where the problem is. As for it not holding a charge. I feel it's the battery. The alt output is 14.2 +- .5. But the battery isn't staying charged past say 14 hours. Also. The voltage level in the dash drops below 9v when the a/c fan is on. The alt may need changing as well. But I will replace the battery first. Maybe that will fix everything. Like I said. Stupid Ben frankllin

 

Yeah it's not the ****ing battery. Stupid piece of **** stranded me this morning. Started up and ran fine for two days. No problems. Just a weak battery and now it won't start. Hell it won't even click most times. I have to get under and tap the starter just to get it to click The relay clicks and I know it's getting power. ****ing thing just won't turn over. Idk what's wrong with it. The battery had a good charge going there. 14.6 volts. So I know it was charging. I love that jeep. I love it so much it hurts but if I can't fix this starter and charge issue I have to sell it. I can't have my son in it with me and the damn thing strand us some where If someone has any ideas. Let me know. I'm too tired and to pissed to think right now

 

I had a problem in one of my Jeeps where the battery kept going dead after a couple of days. After swapping out 3 batteries I changed the terminals and that was the problem. They looked OK, too.

-E

 

Try tapping the starter a bit harder. Sounds like you have a bad starter to me. Don't be afraid to get out the BFH and give it a good whack either, just don't whack it so hard that you dent the case.

 

I'm pretty sure it's not the battery. I hooked a marine battery up to it and nothing. It's gotta be the starter or start solenoid

 

Yeah i'll be keeping my account here, ive been trolling through threads and there is a lot of cool people and jeeps here.
I tried the BFH trick on my starter and nothing, i have also tried jumping the terminals on the starter and again nothing. So i think it has to be a connection problem. Does any one know how often battery cables go out?
And what is the little rectangular box next to the battery that has 7 wires coming out of it?

 

Yeah. I narrowed mine down to the starter it's self. Not to say there isn't a short so
Where too but. Az for right now. The starter is the problem. I fear that the alt is going as well. I've never seen a volt gauge go down to 9 volts with just the fan going so. Starter alt and battery. Then it's fixed.......for now. Is this box. 3inches by 10 inches with a cap on it??

 

I figured out what that box was, its a starter relay. but that wasn't my problem, turns out it was my starter after all.
I had my starter checked at auto zone and they said it was good. I didn't want to believe them cause i didn't hear my starter turn over... but i did. Then i replaced my battery and starter relay and no change. Tried the BFH and nothing. So i took my starter in to napa and right away that said it was bad, lucky for me the P.O. got the last 4 starters at napa. Life time warranty FTW!
So she lives once agian!
What i have learned from all this? Autozone sucks.

 

I think that varies by area. My auto zone here is awesome. They let me in the back to look for parts when they are busy. Let me use tools in the store. And. One of the chicks that works there is a jeep expert. Her and her husband rebuild them. They have 6. 2 yj and 4 xj.

 

battery cables sound corroded.. happened to me. pull ur postive terminal from the cable if you can and wire brush that bistch! or.