Wife was driving the truck and the bat light came on. Of course she never told me and she drained the bat and pulled over to the side of the road. Tested the bat and it was fine, recharged and replaced the alt with a rebuilt unit. Light was off for a minute and then came back on??? I checked the fuses and all I can think of is the alt is bad???

Since the connections were right on the alt is there anyway they could have given me a wrong alt and that it worked for a minute and then the system requirments put too much of a load on it and fryed it??

 

I gave up on parts store "rebuilt' alternators a long time ago... About 75% would fail within 3 months. Most rebuilds are now done by children in dirt floor shops not in this country.

A rebuild by someone who knows what they're doing and actually replaces components is a different story. Hard to find in our "what's the cheapest option" society, though.

But for you: Get a multimeter and test the voltage at the battery with engine running. If less than 13.2 volts: Problem.
Check voltage at the big terminal on back of alternator. If less than 13.2, alternator is defective.

If much more voltage at back of alternator than at batter, cable issue.