Today in my 97 ZJ (4.0 auto), periodically (every few seconds), all my dash gauges go dead and drop to zero, and all my warning lights snap on, then in a few seconds everything goes back up to normal, then it drops again, like a switch going on and off. There's no perceptible change in the sound or feel of the engine when this happens; no drop in power or revs, not even a hiccup, and the engine starts back up after shutting off. Weirdly, the power windows will not move whether the gauges are up or down.

So I'm inclined to think the generator's OK, but that there's some sort of short to the chassis electrical. Am I on the right track? Any ideas?

UPDATE: I have isolated that when the gauges are off the following are NOT affected: AC, lights, Compass, auto door locks, brakes, steering. I have checked all the fuses under the dash and under the hood.

All that seems affected is the instrument cluster and the power windows. Weird.

 

try to disconnect your batt clean the terminals and re attach...the same thing happened to me

 

I would take it to an Auto Zone, Pep Boys, Advanced Auto or someplace of the sort and have a staff person test the alternator while on the vehicle. I guess a shop could do it to for a price.

 

also try wiggling the fuses. I've had some get loose on me before and it did the same thing, no idea how it would've happened though. just shut off every once and a while at random. If they are loose just stick a flat head in there with the fuse out and bend the fork back (with the battery disconnected of course)

 

Thanks everybody. I tried all of the above; also I checked the ground on the radio, as I've been told that can cause this.

I'm down to blaming the ignition switch. While driving, with the gauges jumping around and the windows not working, if I turn the key just a little further (between On and Start), the gauges recover and the windows work. I've ordered a switch ($35 shipped online -- it was $64 + tax at the local auto parts stores, God knows what the dealer would want), and will try to put it in this weekend. In the meantime, it drives just fine, and every few seconds, if I glance down at the right time, I can see how fast I'm going and if I need gas.

I'll post again after I replace the switch.

 

Swapped in a brand new ignition switch, and the problem is unchanged. What now? I'm kindof scared now....

 

This may seem weird but i had a subaru that had a plug under the drivers side dash by the pedals that was meant to stay unplugged and if you were to plug it in it would do something similar to this. I doubt that is the case for this but maybe? Also have checked all of your electrical connections you can get to? unplug the wires that connect to all of your sensors and if they're corroded spray a little wd40 are in there then some compressed air. Also check the wires through the firewall to make sure the sheathing is intact, and check your battery connections and grounds too.

Hope some of that helps and good luck, keep us posted

 

I had that problem too and solved by re-torque battery cable. Check the battery for bad cell or crack post inside the battery.

 

Wow. OK, here we are... Following advice, I have done all the following without a change in symptoms (even a little change):

Cleaned battery terminal posts to shine, replaced clamps
Replaced corroded cable running from negative to body
Removed/cleaned/polished positive cables running to block and to another ground post under AC compressor
Opened/cleaned/tightened connectors I could reach, checked all wires I could see, taped where casing had cracked/worn thru
Swapped out battery for good one from wife's truck (swapped back after test)
Checked all fuses
Pulled instrument cluster, cleaned contacts

One thing I haven't mentioned: The dopey graphical display under the dash, the one that tells me which doors are open and how many "miles to service" is getting power (it lights up) but no data -- it displays two rows of square blocks. The overhead computer -- compass, etc. -- is working fine.

I've pretty much reached my limits. I may have to take it to a mech, but I'm terrified (after hearing many tales of mystery electrical problems like this one) of a long, costly series of "tries" that don't find/fix the problem. I'm REALLY afraid it's the ECM... Which means I kiss my Jeep goodbye, which I can't afford -- there's a reason I drive a 13-year-old jeep.

 

So, I put the dash back together and went for a drive... 1 minute in, as I was noticing that the gauges seemed to be working, there was a puff of smoke from the center vents and burning smell. Right after, the voltmeter dropped to 0, but the other gauges stayed up. I drove back home, and popped the hood, and saw that I had forgotten to reattach one of the grounds after cleaning it. I reattached it and went for a drive, and voila! Everything works again!

EXCEPT... the graphical display. It's dark, dead, and I suspect that puff of smoke is when it died. Was it the problem all along, and did the problem clear up because it died? Or was it a coincidence?

I don't care. I always thought the thing was silly anyway, my car works again, and I didn't spend a fortune sending a mechanic on a fishing expedition. Yay me!

Now to decide --- is it worth the trouble to return the unnecessary ignition switch, just to get back the $20 that will be left over after the restocking fee and shipping?

Thanks for the help.

 

I would keep the one you bought, and the old one for a spare, personally. The puff of smoke you may want to keep your eye on as that could be wires that have heated up enough to melt the insulation and are making contact. Watch for shorts because they lead to fires.

 

Glad to hear its working again, grounds can do terrible things if they aren't getting proper contact. As for the display, from what I've read its pretty easy to get into the center part of the dash. Just take off the trim and look around for any connections that look burnt. You can probably spot it pretty easy if you saw smoke and smelt burning. If its not a big deal to you though I wouldn't worry about it too much but do keep an eye on it just in case it sparks up again.