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sevenservices 06-17-2013 03:38 PM

Charging system troubles resolved for good!
I wanted to share this as its the first I've seen this problem on a YJ.

I started getting weird symptoms last winter here in MI where my voltage would spike to 16v! My CE light would come on and the two errors I kept seeing where "charging field circuit short" and also "battery disconected within the last 12 starts".

I learned the voltage regulator is in the ECM. But, my computer is only a few years old. I hoped it wasn't that for sure!

Last week, she finally quit charging completely. Plain and simple alternator failure. Or so it seemed... I pulled the alternator and had it bench tested at the local parts store. It worked perfectly! Darn it... I thought I'd have to go after the ECM. But, the guy at the store said "your connections look like crap, I'd clean those up w/emory paper or sand paper before hooking it all back up". Ok, so I did that. And I redid my grounds.

Heres the kicker... I disconnected the + battery cable when I started taking it apart. When I went to hook it back up, I found my problem. The + battery cable has (2) cables coming into the lead terminal end. One runs down to the starter and the other runs to the power box in front of the battery. The one that ran to the power box was green and cooroded so bad under the insulation that it had actually split the lead open on the bottom side of the positive terminal!

Replaced my battery cables and she's running absolutely amaizing. Over 100 miles now, no slow starts, no sputtering from low voltage, no check engine light and the guage is perfect back at 14v like its supposed to be.

So, Im mentioning this not only to suggest cleaning all the connections, but to suggest pulling off the + battery cable, turning it over and looking for the split w/coorosion on the under side, out of sight.

It was a simple fix, I ran (2) new cables. One to the starter and one to the power box. I attached them to a brass (in place of lead) terminal end w/wing nut. Couldn't be happier w/'er back on the road!!!


sevenservices 06-18-2013 08:42 AM

Went about another 30-35 miles or so... no probs whatsoever. And OMG it cranks over so fast to start. I don't think I've ever had it turn over so fast when touching the key.

Connections... connections.... connections... its all about connections... :)

Stupid wires! ;) lol, just had to get that out!

dmcg 06-18-2013 11:50 AM


sevenservices 07-08-2013 08:09 AM

There is more to this story... continued here:

Ended up having to replace my alternator. It was flaky, I'd lose all voltage then tap the alternator w/a breaker bar and it would make a swoosh sound and the V would come back up to 14v. Probably sticking brushes... thought about rebuilding it but wanted to just go w/a new one.

REDZILLA 09-04-2013 12:21 PM

i have the same issue atm. was driving and the guage cluster went all wacky. gas dropped, bat and oil max'd out. Then a few hours later it failed. i also thought it was a alternator problem. got it tested and it passed. also had it removed and the wire and brushed cleaned. the battery is also holding a charge. so we came to think it was a charging issue in the ECM. any ideas? when the codes are ran, the only code that reads is ambient bat temp. ? we were considering a external regulator for the alt to bypass computer. any ideass? would appreciate the help.

harleydragon 09-04-2013 12:36 PM

put a chevy alternator in it and forget it

BCDonny 09-04-2013 01:09 PM


Originally Posted by harleydragon (Post 4278641)
put a chevy alternator in it and forget it

I think a chevy alternator with built in regulator is the only way to go

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