Interesting charging issue.

I have a 1995 xj with a charging problem. When my jeep is running it will not charge, the grounds are good, new battery. the funny thing is i can reach down and fiddle with the small black box on my alternator and get it to start charging. Ive been told that "this small box is just a junction that almost never breaks." I have found almost no info on the forum about this problem. any help would be appreciated. thanks

Disconnect the battery.

Remove the alternator from the vehicle.

Examine the alternator. Repair or replace as you deem appropriate.

If physically futsing with the alternator restores alternator function, then "cause and effect" tells you that the alternator is faulty. As Joe mentions, time to get the alternator out.

-disconnect the battery and remove each wire connection at the "black box."
-clean and inspect each connection
-re-install each one and try again

the symptoms you are explaining leads me to believe you've got a poor connection at one of the wires. I can't even begin to tell you how many alternators I have "fixed" by fixing their contacts with the rest of the vehicle.

make sure, also, that the posts that the wires connect to are snug in the alternator case (not OMFG-tight-- just snug) and the alternator is bolted well to it's brackets as that's it's ground connection.

birchlakeXJ said:

If physically futsing with the alternator restores alternator function, then "cause and effect" tells you that the alternator is faulty. As Joe mentions, time to get the alternator out.

Click to expand...

Not the alternator at all just the funny little box connector thing, im going to go hook the connections back up and see if somthing was just loose. All the bolts seemed tight but you never know.

Well i just went out and reinstalled everything and it seems to be charging(without messing with connector" so im assuming a had a bad connection. Thanks for the input guys.

:thumbup: glad to hear it!!

That black box that you were fiddling with is the connection point for the field coil inside the alternator which is controlled by the computer. If the connections there are loose then that will prevent the alternator from basically energizing and producing the charge. They don't go out because there's nothing there just a molded piece that puts the wires in physical alignment with the two studs sticking out of the alt.

dave92cherokee said:

That black box that you were fiddling with is the connection point for the field coil inside the alternator which is controlled by the computer. If the connections there are loose then that will prevent the alternator from basically energizing and producing the charge. They don't go out because there's nothing there just a molded piece that puts the wires in physical alignment with the two studs sticking out of the alt.

Click to expand...

It also has a ground wire in it, the biggest of the three wires. Seems redundant to the mounting bolts.