New Member Desperate for Help

Hello everyone. I need some help....

vehicle: 1997 Grand Cherokee 4.0 2wd

problem: #1-speedometer goes crazy (even when sitting still), causing tranny to shift itself into overdrive, and I have to pull it into Low and shift it out #2-"Check Engine" light comes on, most usually in conjunction with the speedo thing #3-today, it did both, along with dying, leaving my wife stuck in traffic. She said the following happened...the check engine light came on, then the speedo went nuts, then a few minutes later it died (no radio, gauges, nothing, even with the key on)...she pulled over, put it in Park, turned off the key, turned it back on, and it immediately started and she was on the road again.

any thoughts? anyone else had this problem?

I would guess that the Speedo and Trans issues are Speed Sensor Related. Since your engine light comes on there are codes to help diagnost the problem. Try tunring the key on and off and on again and count he flashes on the check engine light like code 34 3 flashes then 4 flashes. Either drive it to Auto Zone and have them scan it for you.

Along with checking the stuff added above I would check for loose battery cables, rusted or missing ground, check and make sure that the top battery posts are clean and making good contact with the cables, it dose not hurt to go and buy a battery post cleaner.

If you live around trees check for rodent nests and wires that something may have snacked on.

Hook up a volt guage ($6 walmart) and check that power is comming and going from the positive cable to the power box, and check power levels around every part of your jeep.

It really sounds like a floating ground, the bad thing is that it could be any place, but I would check my battery first to make sure its sending power out, try twisting both cables while watching your meter.

I had a 93 Lincoln with Vac Dig guages, one day it started going nuts, and the car allmost cut off when the fans turned on, even tho the cables were somewhat ok on the battery the ground wires had over time lost contact with the car, I cleaned up all the grounds with my drem and it worked great, and this just happend right out of the blue, no warning.

Hope this helps, if you find out whats wrong I would like to know.

Oh man...rodents! I've seen them do some horrible damage. I've seen an insurance company total a Caddy Seville that had rabbits snacking on the wires.

Good suggestions all. Start with the easy checks of wires and plugs, and get the codes.

You would think that some of these car makers would put some sort of braded cable on some of those wires.

Alot of people would think about wrecking a car for the insurance moneys but I think that getting a $3 jar a Jiffy and putting it on your PCM would do the trick. LOL

I was even thinking about putting that fake over the hose steel braded hose stuff over some of the exposed wires under my JGC but I havn't had a problem.

I have to say that my ZJ has some messed up places under the Jeep with wire out in the open, like the horns, right under the bumper on the pass side, when I replaced them (allmost $100) they gave me a 12" new conector to add in the horns to the new plug style my 1972 GTO horns still work and they are made out of Alum.! go figure.