Alternator went kaput

So in previous post one of my issues i thought culprit was body controller, due to wacky voltage readings and alarms at gauge.

Ever since i thought my "cleaning" fixed it.. i have maintained a 13.9 volt reading when nothing on but engine, but noticed serious dropped in mid 12 (battery charged) range.

Well today had truck idling while I installed ELD crap and was cleaning and putting some panels back on. I went to move it back in spot when alarm went off was at 12 volts and light at volt gage on.

Did voltage output test when engine off batts were at 12.1 when engine on no other loads dropped to 11.95v. I also did load test and it dropped to 11v. Last test i did once I had alternator out, i did diode test with voltmeter. Thats putting volt meter to diode position.. neg lead at positive post of alt and pos lead on housing got 450 millivolts , suppose to show reading, but when swapped polarity you not suppose to get a reading, but i get 1.7 volts (.1799mV)

Gonna go to a local alt shop tmw see if they can bench test and rebuild if needed will update if all good and hopefully if it cures other electrical gremlins i have experienced.

 

Quick trick i was taught back when i was a mechanic for xhrysler and hyundai . even in manufacturer schools it was a "one of the quick chexks" ... ive even seen few youtube vids that show this method .. makes sense all diode is a a one way valve for the polarity.. the dvom supplies the test voltage.. im going by how i was shown its not def proof thats why i had it bench tested by local shop and it was bad.

UPDATE: installed a delco remy 160 amp (smelled funny out of box lke electrical fire) all good and charging at 14.1 and voltage drop at batt is 13.8-9. only grmelin I noticed that my temp gagge that didnt really work now works fine.