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jefferyc22 02-03-2013 12:18 PM

Alternator/exciter charge issue
Seems to be a loose exciter pigtail connection on the alternator but my symptoms are a bit random.
Please only respond if you have had an issue with this or understand electrical theory.
Alternator itself can and will output 14 volts charge when working(measured on my Fluke)
Alternator will randomly stop charging but can be re engaged by screwing around with the exciter pigtail.
I sprayed down both the male and female side of the exciter pigtail which seems to have helped and little but it still randomly connects and disconnects.
While driving voltage is right at 14 and then will dip down to battery voltage....12.5(this is the exciter loosing connection)
The scary part is that after it sits at battery voltage for a couple minutes the volt meter drops to zero....check gauges warno comes on and I know the battery voltage truly is dropping off that fast because the 1 farad cap has an alarm that goes off at 10 volts.
Battery test came out to 450 amps which is low but not bad.
Are these alternators known to have exciter issues?
At this point I'm assuming the severe charge/discharge cycle has taken it's toll on the old battery and has made the issues more severe.
The battery does not seem to be parasitic as resting voltage is right at 12.5 and only drops a few .01's of a volt over a few minutes.

Fatherof2 02-03-2013 02:01 PM

I'm having the same problem...let me know if you get any good answers.

Jerry Bransford 02-09-2013 11:40 AM

I can only say our TJ's alternators actually have a pretty good reputation and there is no exciter circuit issue that I have heard of. I'd have the battery load tested and the alternator checked at the same time while the tester wiggles the connector. Good luck with it, I wish I had an easy piece of advice for you but...

jefferyc22 02-15-2013 08:35 PM

The culprit was the brushes and slip ring worn out to the point that physical connection was lost intermittently.
IMPORTANT NOTE if you have a 2000 Wrangler:
It is the only year to have an externally regulated alternator and alternator is unique for that year only and is quite rare. The voltage regulator is in the ECM(obviously a very stupid idea)
Mods: Please edit title to reflect issue being year specific as this may be helpfull in search function.

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