Alternator went out! What's next?

[73chgrSE]

Damn I just replaced the spark plugs and did an oil/filter change and went for a short cruise to check it out and now my ALT gauge is showing discharge. I returned home & unhooked the battery and it cut off right away.

My brother in law said it's 90% chance that it's the alternator. He's probably right, but what else should I check before just pulling it and replacing it? Can't these be fixed with new brushes?    Wires checked out OK.   

[green69rt]

Damn I just replaced the spark plugs and did an oil/filter change and went for a short cruise to check it out and now my ALT gauge is showing discharge. I returned home & unhooked the battery and it cut off right away.

My brother in law said it's 90% chance that it's the alternator. He's probably right, but what else should I check before just pulling it and replacing it? Can't these be fixed with new brushes?    Wires checked out OK.   

If you end up pulling it, take it to your local parts store and have it tested before buying a new one, just to make sure.  Sometimes you can replace brushes and diodes, I don't know about you particular unit.

[John_Kunkel]

My brother in law said it's 90% chance that it's the alternator. He's probably right,

Don't know where he got that statistic, could just as likely be the regulator. Easy enough to test, refer to the FSM.

[73chgrSE]

VR checked out ok with the meter.

UPDATE!

I pulled the brushes out and swapped them with ones I had in another alternator I have. Its a single pulley alt so I cant just put it in place of mine. They were in better shape than mine But it still shows the same discharging condition.

[stripedelete]

Take it to a rebuild shop.   The Chinaman's reman will leave you along the side of the road.

[73chgrSE]

 

Take it to a rebuild shop.   The Chinaman's reman will leave you along the side of the road.

[b5blue]

Most parts stores will test charging in the car for free.

[John_Kunkel]

VR checked out ok with the meter.

Meter proves nothing.

Assuming it's a '70 or later, remove both field wires from the alternator, ground one of them (either one) and apply battery voltage to the other. Start the engine, if the ammeter shows a charge, the alternator is good and the VR or wiring is faulty.

[73chgrSE]

I put the meter on the battery while running and it was still only at 12.3 or so.

New alternator fixed the problem though. I could see how the old one was completely blown out in 1 of the 6 squares on the back.

[Nacho-RT74]

One diode went out. Easy to service by yourself for squareback alts. Diodes banks are available around for cheap and they are bolt on pieces.

Scroll down around half of page and will know how.

https://www.allpar.com/history/mopar/electrical.html