A few weeks ago we were headed to a Christmas dinner when the service charging system light came on. Barely made it to where we were going when it killed the battery. I went back later and charged it to load on a trailer. Had to disconnect the hot wire to the alternator because it seemed like the regulator stuck and was shorted. Replaced the alternator. Christmas eve noticed a hot smell coming from under the hod after we went to town. Alternator was really hot. And the we go back to the friendly warning on the dash about the charging system. Put my meter on it, not charging. Replaced the alternator once again. My meter is saying is putting out 15.5 volts, which I think it pretty high. Any suggestions? I'm not sure what else I can test and not just change parts without taking it to the shop. I thought it may just have been a bad rebuild the first time but now I'm not so sure.

 

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Bad rebuild, over cooked battery, loose ground wires?

 

Based on what I've read as far as specs, 15.5 may not be too high. Voltage output as high as 19 volts is noted in the repair manual as acceptable.(yeah, I thought that was crazy too but I read it in more than one set of specs. )
Also, the alternator does not contain an internal regulator and it is actually referred to as a generator.
The alternator regulation is controlled by the ECM or BCM(I can't remember which one )
Sounds like something is killing the alternators. I would check the wiring as Oldblue suggested. Could be a loose ground or shorted wire somewhere.

 

Welcome to the site

Where are you take your meter reading from?

I would be curious to see what the voltage reading would be at the battery and under the hood.

 

Here's a concept, just a suggestion, if the ECM or BCM is controlling the voltage, then perhaps a 30 minute labotomy will reset the computers, you really should disconnect the negative cable at the battery whilst you inspect the grounds and the fuse block halves to avoid surges anyways. I'm thinking it's cheaper the throwing more parts at it!

 

Taking the meter reading under the hood. My next thought was to pull the neg. cable and do a reset and see what happens. I hate throwing parts at something, but I would rather do it than pay someone else to do the same thing. Next option is to take it to the shop, but was wondering if they can run a scan tool to diagnose the issue or not.

 

Scan tool might not catch loose connections, be it ground or fuse block

 

Pulled the neg cable for a while tonight to reset the ecm. Drove it about 40 miles. Checked the output when I got back home. 15-15.5. No codes though. Guess I'll just see what happens.

 

Fingers crossed!, this reset the computer systems, and it's back to normal.

 

Seems to me that the battery would have been disconnected during the alternator change. Or, it should have been......which would have accomplished the same thing.