Any guesses as to what is wrong now?

My 1990 XJ AW4 4.0 shut off randomly again. It lost all power, except for the key-in-ignition-door-open buzzer. The radio wouldn't come on, and it would not crank. Completely dead.

I have no idea if this really matters, but I opened the hood and messed around with the wires in the power dist. box. I pretty much just pushed on them, and tried starting again. Started fine, and didn't shut off on my way home from work. Any ideas as what this could be? Battery cables and grounds are fine.

CPS was replaced less than 2 weeks ago, although if that was the culprit, it would be cranking and the accessories would have power, just no spark, correct?


Any ideas? At least the Jeep was nice enough to kill itself as I was parking on my return from lunch.


Edit: Upon further inspection of the power distrubition box, I have found at least two wires that are still "in tact", but the shielding has corroded away, and their connections are very flimsy and poor. Does anybody know what each of the wires that plug in to the PDB do? Not the ones that are held in place by a bolt and nut, but the ones that are right below them. There are 3 or 4 of them.

Thanks

i would double check to make sure the battery cables are clean and tight especially between the cables and the battery post

As I said before, the battery cables are new, squeaky clean, and tight. They are not the problem, nor are their connections.

Thanks

My guess is a bad ignition switch. I do not mean the lock cylinder but the switch mounted about 1/2 way down on the column. There have been several posts on igniton switch so do a search.

If the switch goes bad the power will not flow. Basically all "switched" power goes through the ignition switch. Next time it happens check to see if you have head lights, that will nail it down it is your ignition switch.

I replaced ignition switch at 145,000 miles on my 88 XJ. It should be less than $15 for a new one, replace it. Do it yourself or pay someone. My advice is to change the head light switch while you have the dash apart.

I´m not getting the power distribution box? Do you mean the starter relay, silver box, between the relay rack and the battery?
If we are talking about the starter relay, most all power comes from the nut in the back of the relay. The fusible links hooked to the back of the relay, fuse most all power. One of the green coded fusible links, is the main power to the ignition switch, red wire, not the biggest, not the smallest, 12 gauge I think. There are a few fusible links, all green coded, all with red wires, trial and error is the easiest way to tell them apart.
Sounds like the iignition switch may be bad or the nut may be loose on the back of the relay. Or the main wire coming from the battery to the starter relay junction. The ignition switch, power wire goes through the major connector at the back of the fuse box in my 88, think your 90 is the same. Wouldn´t open the connector at the back of the fuse box (inside the engine compartment/firewall driverside low), some kind of gunk in there, that´s a mess to clean up (ask me how I know that).
On the back of the relay, there are some letters, that tell what the spade connectors are for. B/S/I/G and the big one is BATT, B is ballast, fuel pump bypass for start, S starter solenoid, I ignition, G is ground. Have seen some different markings though.

Yup, the starter relay is what I was talking about. I've always seen it referred to as the power dist. box, even in a couple of write ups.

Anyway, does anyone know what color the I (ignition) wire should be on the starter relay? Most of the wires plugging into it need to be replaced, asap, and will be Thursday.

How in depth is it to change out the ignition switch? I changed out the headlight switch a couple of weeks ago. Was a PINA, but got it done without problems. Does the steering wheel need to be pulled? Any write ups? Would this be one of the parts I would want to purchase from the dealer?

I've got my headlights on a heavy duty harness from the battery. When it does it again, and if it's the ignition switch, should I expect my headlights to stay off, correct? The dome lights would be on however, right? I did not look for those this afternoon.

The "I" wire, is green (I believe), the "I" pole on the Start relay, is powered up by the ignition switch in the start possition. The "I" pole is the + coil winding in the relay box. The G is coil ground (goes through the neutral safety switch to ground.
Power to the ignition switch, is one of the red wires running from the large lug on the box.
Most of those red wires running off of the large lug at the back of the Starter relay box/power distribution box, power sub systems, one is continious power for lights, accesories and such, one for the ignition switch, one runs to the ECU/ECM etc. The alternator to battery feed, also meets there.

Terminology messes me up some, I´m an old school mechanic.

Intermitant problems are a pain, often easier when it quits and dies, to troubleshoot.