97 XJ, stock engine, stock wiring. Plagued with charging issue- previously on this website I saw a recommendation to clean all the grounds. After doing that we took the jeep out 4 or 5 times with no problems. Today the problem is back and worse.

I will be driving and the Check Gauges light comes on and volts are zero. I have to turn the engine off, unplug and replug the rear most computer plug.

Then when I start the engine, it will charge until we start rolling and now that it is worse it even quit charging while standing still, leaving us running on battery.

I thought I had solved the problem by cleaning the grounds. Now I am wondering if I have iffy caps in the alternator and once it quits charging, the computer keeps it off. I would be thrilled if all I have to do is replace the alternator. When this happened before, OReilly said the alternator was good two different times.

Previously replaced the computer- not necessary. Appreciate any help.

George

 

sounds to me like an alternator or a ground

 

I had a similar issue, alternator tested good at the parts store. I messed with it for months, sometimes it would work sometimes not, finally took it to the local mechanic, he put a new alternator in (I was convinced it was the ecm) and that seems to have cured it (so far).

 

Unfortunately I already bought an ECM and nothing changed. After some research, I am going to check the fusible link from the alternator. If OK, replace the alternator. I have a battery/alternator meter that says the jeep alternator is not charging and on my wife's car shows hers charging.

 

90 amps? or 120? After I rule out a burned fusible link (green wire at the front of the power center) I will get an alternator.

 

For these symptoms, if you have already replaced the computer with no change, the alternator is the likely suspect.

Bench testing of alternators is very hit and miss. With a lot of miss. There are plenty of "escapes" (alternators that are bad that test good) with parts stores bench testers.

If you have actually freshened grounds (not just inspected them), I'd spring for a new alternator.

 

I actually removed, cleaned, sanded all grounds but the one on the intake, couldn't get to it. I plan to first jump past the green wire fusible link at the front of the power center, just in case and move on to a rebuilt alternator.

 

The conclusion: I have again proved an auto parts store can't do a good job of testing an alternator. I replaced the alternator and we have gone wheeling 3 or 4 times with no problems.

Thank you all for the helpful suggestions. My grounds are sanded, the cable ends (copper) are bright and all is good. Happy wheeling! and happy holidays!