And the end result is awesome Jerry! That's one good looking XJ.

 

Well...I decided to run this thing on my route again this week and after one day with no issues, it did it again the second day. BUT...I now have another clue to work with. While pulling up to a mailbox, all power went away again (everything electric stopped....radio, blower motor, etc.) and the motor died. I pulled over and with the key still in the "on" position, I began moving the wiring harness to the ignition switch (I now keep the plastic cover around it removed just to make it easier to do this) but nothing happened. I was on a dead end road and it was very quiet. All of a sudden within less than a minute, I heard a small "tink" and all power was back on. The best I can describe it was that it sounded like a little metallic "click" like that of a breaker, relay, etc. It was very faint, but seemed to be coming from behind the dash. I'm really wondering if there is some sort of faulty relay, breaker or whatever back there. Tomorrow I plan on tearing apart the underside of the dash so I can get up in there and look around. My other thought is the relay in the PDC that is labeled "ASD". I wish I knew more about the whole auto shut-down system and what triggers it and what exactly it kills. If it kills all power to everything, then I suppose a bad relay there could be the issue. I wish I could simply switch this relay with the ASD relay from my other '96, but this particular Cherokee must have been a "mid-year" 96, as often when I buy parts for it I have to get parts for a '97. I found that out when I had to replace a washer pump. Anyway, the relays for the ASD are completely different on my two '96 Jeeps. If anyone has any ideas in terms of that little noise I heard though as the power all came back on, I'd be glad to hear them. I sure hope I can find something obvious tomorrow.

 

There is a 7 pin connector on the very bottom of the steering column, the red wire (fan/stereo) has a nasty problem of melting, I am currently in the same boat as you but have found a mickey mouse fix for now until I can find a new connector.

Remove the plastic around the steering wheel, !UNHOOK THE BATTERY!, locate the red wire, clip off the broken/melted part of the cable, remove the old cable from the inside of the connector, remove 1/8th of an inch of the sheath, insert the cable and crimp the cable (using needlenose pliers worked for me).
Let me know if this works for you, I accidently found the bad cable and took it out without thinking about what I was doing ( had no problems before this), this all started with the headlight cable not being inserted correctly :@

 

Thanks nquinn for the info. I actually think I've narrowed the problem down significantly. When everything dies, I've found that if I move/jiggle/disturb this large clump of wires that is zip-tied together up near the firewall under the dash, all power will come right back on. I suspect that this is the area where all the wiring from the engine compartment comes through the firewall. Once this "polar vortex" type weather here in Wisconsin finally ends this spring, I plan on cutting all the zip ties and inspecting every wire and connector in that clump very closely. I'm really thinking it may be a wire that has something to do with the neutral safety switch, as the quick power loss would often occur when I'd be shifting from drive to reverse or from drive to park. Since I've already replaced the NSS twice, I don't think it's the switch itself. Anyway...the problem hasn't happened for over a month now, since the last time it did, I crammed the clump of wires rather "harshly" up against the firewall. Who knows...maybe I pushed some loose wire back into its connector!

 

This is about the closest thing I could find to my problem on my 99 XJ. I just completed the nearly 3000 mile Hot Rod Power Tour in my 99 XJ. It ran fine the whole trip.



Driving it had a split second hesitation. Then it ran fine. Low fuel light came on and I could watch the fuel gauge drop. At first I though a hose came off and it was draining the fuel tank. No fuel leak. Stopped at a traffic light and the Jeep shut off. Still had head lights, cranked but no fire. Drifted in to a parking place and it started and ran fine.

Then I was getting off the interstate and it shut off drifted into a lows in neutral, it started on the key as I cranked it drifting. Has run fine since.

I have jiggles wires and cannot reproduce it. It appears the computer is loosing power.

Is this close to your experience?

 

As much as I hate to restart old threads, this is exactly what happened to my 96 Cherokee this morning. Noticed the headlights flickering a bit this morning, never noticed that before and a slight rough running of the engine. But then again, it was -20F here in WI this morning

Anyway, all good until I stopped at the ATM machine and put the truck in park, poof everything electrical gone for about 3 seconds. I mean everything, even the radio lost its memory settings!

So, tonight, out to replace the positive battery cable (while nice and tight, the wire ends are exposed and corroded) and check the PDC fuses and connection in the front.

Did the OP on this thread ever figure out exactly what his issue was with the jeeps he was using to deliver mail? I just ends with "I pushed hard on the bundle of wires on the firewall"

 

The clump of wires up under the dash is indeed where my problem apparently lies, although I haven't experienced it in almost 6 months. I believe this mass of wires has a large connector where a bunch of wires come out of it. It looks to be a plug-in connector of some type where you have like a male and female plug that join together. I suspect either I have a loose wire or wires in one side of that plug or the other, but by cramming it up under the dash and putting a big zip tie around the whole bundle last summer, I must have forced the broken wire/loose connection to make better contact and it hasn't bothered me since. I'll probably take the whole mess apart this summer when it's warm and the wires are flexible, although I hate to mess with it now that the problem has disappeared. I used to have the same issue as you had today. Sometimes putting the Jeep in "Park" or "Reverse" would jar the loose connection just enough to cut all power for just a second or two. I also replaced all the battery cables (positive and ground) before I finally isolated the problem. I still think I have a bad ground somewhere else as well, but that too will wait until summer.