Hey guys. So today while wheeling my battery gauge dropped down to 9 out of nowhere. Check gauges light came on. Figured I should get home so I left and while driving my gauge went to about 12 then dropped back down to 9. The idle was also really high. So driving back on the highway my radio went out. Then the windows. Then the gauges went out. Then I lost all power. Could this be a bad alternator? Its a 2000 I6

 

I had the exact thing happen to mine after wheeling. Replaced the alternator and it was fixed.

I think though what may be happening is the field could in the alternator may be getting dirty enough to cause these problems. Not a hundred % sure I couldn't have fixed the alternator myself.

 

Is there green muck on the battery terminals or any electrical connections? Verify the battery voltage with the engine off then running with a reliable DMM.

 

Regarding suspected alternator issue: Some simple checks and diagnostics can point to the way.
Simple things first: check your connections. Battery terminals clean, clamps clean and snug, connections with the alternator clean and snug. Clean the grounds.
Next, check battery voltage key off. Then with engine idle. Voltage should be at least 0.5V higher then with key off. On-car load testing: engine idle, turn on as many accesories as possible (except the rear window defog) and see how the voltage holds out.

If with engine idle your voltage is not more than 0.5V above, dont condemn the alternator just yet. It could be cable related as well, but more about that when we have to.
Alternator testing in one of your part stores is free, I understand...

See how this goes and let us know.

 

Check your grounds loose wire maybe?

 

Battery terminals are clean. Battery tested 3 volts so it's dead as a door nail. I'm gonna pull the alternator tomorrow and clean it up.nothing looked loose in the bay. I should note that I went through a huge mud hole right before this started happening.

 

I was looking for new alternators online and found this one:

I checked around and everyone is happy with there stuff. No bad reviews. But if i do upgrade to the 160 amp, do i have to upgrade the wiring? or can it wait a bit

 

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Like Caveman mentioned, getting them packed with mud and rocks doesn't help anything, I'm not quite sure what that would ruin though. (short of the rotor lunching it's self, and/or the stator) If you just take it apart, clean it well, then have it tested as Roler mentions, it may well work. Crud may be preventing the brushes from making contact on the rotor's slip rings, "ferrous" pebbles, (like the stuff that sticks to your magnet while picking up nails in the driveway), could short the positive diodes. (OK, but you won't get juice from it). If you DO clean it, note that there is a hole for a hairpin/paper clip wire to feed in through the hole to hold the brushes in while you put the cases back together. Might be lunch, maybe not.

You should disconnect your battery and get a charge on it asap. They really don't like being that low!

 

3 Volts....thats kinda below spec ;
And yes....that kind of details you should mention indeed...

 

yeah i basically ran the jeep on battery till it wouldnt run anymore. im gonna get a charge on it tomorrow when i get a chance. then had AAA tow me back to school. I talked to the driver who is a mechanic as well and he said alternator is done and a couple other car smart people i know said it was the alternator. I wanna get this running as soon as possible. are the alternators from advanced or napa any good?

 

Can't help you with that, since we don't have those stores here

 

Anyone deal with alternators from advanceauto or napa? I know autozones are crap

 

I usually go with Napa. Also last year Brookings Napa gave me a replacement starter, even though the warranty was not clear they needed to. Also they seem to be everywhere.

 

The napa only shows reman ones. Are they still good?