High voltage

Yup. Internally regulated. Alternator will not shut off. I would double check with a meter at the hot post to confirm high.

 

Alternator, we just had this happen a few months ago

 

if there not bad or shorted yet. They will be soon if you keep driving it

 

I wouldn't toss an alternator at it without running a few voltage checks first. I've seen trucks where the voltmeter on the dash pegs out at 15+ volts but only putting 13.5 to the batteries because of a rotted battery cable end. Alternator was 100% fine. Diagnose before throwing money at a problem. Just because 7 other people had the alternator as the issue doesn't automatically mean yours will be too.

 

Mine was running high because of one shorted battery. Wasn’t as high as yours, and wasn’t consistent. Thought it was the guage. I kind of ignored it, till an obvious sulphur smell on a real hot day got my attention. I would guess disconnecting the batteries would tell right away if you have a battery or cable problem. I disconnected the bad one till I could get 3 new ones.

 

Make certain all batteries are getting the same voltage first. If they are, bad alternator.