I have a gas 2003 f350 5.4L with 2 batteries. I bought a new battery and had then had the alternator tested to see if that was causing the problem. Oriellys tested in the parking lot and said my voltage regulator was bad. Bought new oriellys alternator part #(GL-529-RM) and installed

Noticed 3.2 volts meausred off the back of the new alternator. Brought back the core and had them bench test the core and it passed. I then had the new one tested in the parking lot and it failed. The voltage regulator was bad. Oriellys exchanged the alternator for another new one, which also tested bad and needing a voltage regulator. They bench tested the first bad one and the machine froze up during the test and said it was most likely bad.

I am still reading 3.2 volts off of the back, but statistically 3 bad alternators is not possible. If I remove the discconect the hot terminal on the battery, the engine quits.


I see fireplug mentioned in other posts, but cant cross reference that word to an actual part.

 

did you test the other battery? How do you know the one was bad? always a good idea to load test it off the truck as well.


Usually if you have one bad the other is as well. That maybe the cause of the resistence.

 

This is more common than you think with "rebuilt" alternators.

 

It is also quite possible to get 3 bad alternators in a row from O'Rieley's. Before I swore off buying crappy parts from crap parts stores, I once got 3 bad starters in a row from Checker's. 3 Starters swapped in one day, on a big block Dodge with headers. Yeah, I was pissed.

I would make them test the "brand new" alternator before you even take it out of the store. Or better yet, just get your money back and go down to Napa or the Ford dealer and just get a good quality part to begin with.

My 2 cents.


And I second the idea that you really should test both batteries when you run a dual battery system.

 

In a "dual battery" system, it's electrically a single (large capacity) battery. It isn't good practice to replace half of a battery. It will work, sort of, but plays hell with the charging system.