I have a 98 Grand Cherokee 4x4 4.0L. A couple weeks ago, my girlfriend calls me while she was driving it on the highway and said that the check gages light came on and the battery gauge was on zero and the check engine light turned off (which it is always on due to a bad fuel injector). I told her not to worry about it and I'd look at it when she got home with it. On her way home, she said that at first the windows wouldn't roll down. She got back on the highway and she said slowly all the dash lights came on until everything was on. She said that while this was happening, the headlights started getting dimmer along with the dash lights. When she got in the driveway, she put it in reverse to back out onto the street and it died. I came out and managed to push it in neutral back onto the street.
We replaced the battery, battery gauge will go up to about 1/4 of the gauge then back down to zero.
I pulled the alternator today and took it to Auto Zone to have it tested, tested out perfectly.
It's a primary means of transportation and needs to be back up and running ASAP.
Any help is greatly appreciated!

Obviously it isn't charging the battery. My first thought is to check the positive battery cable for corrosion - cut the insulation back maybe 6" from the battery and if you see a whitish buildup, that could be the issue. I've had a couple of vehicles with this problem.

If your cable is ok, then there is some electrical management issue....and I'm the wrong guy to be commenting....should be someone along shortly.



...8k...

There is probably a fuseable link going from the battery to the starter. Also check the small wire on the alt., one time I had the wire break but the insulation did not. Use an ohm meter to check it out.