I just want to verify I am thinking straight on this. I was having an issue with the altenator over charging one of my batteries and not charging the other. Took to Autozone and they checked the voltage regulator when I started it. They told me it was bad and I needed a new altenator. They told me the voltage regulator is built into modern day altenators. I went with it not knowing different. Changed the altenator. About a mile down the road my voltage guage drops from 14 to 9-8 and my check engine light comes on. Took the altenator back, had them check it, it was bad, and I got another to put it in (had them check it before I walked out). Put in the second one. Same issue and now my A/C is randomly on for some reason. Now since the voltage regulator is built into the PCM and the A/C is controlled by the PCM am I right in assuming its the issue? I read some thread about resetting the PCM but I dont think it would help in this case.

 

It could be the PCM. It would be great if you had a friend that you could borrow one from for testing.

 

Yea that would be nice. Seems like the only way to for sure tell is to swap it. There isnt a test I can do to see if it is.