Mine turned out to be a bad diode in the Alternator.. It tested good an whenever it decided to it woukd drop fast..Alternator tests good .
Thankfully no pcm replacement needed!
I was going to put one of those external regulators on it
too but replacement worked.[ good diode ]

 

Fluctuating voltage is often caused by a bad alternator. I kinda felt all along that wasn't my problem because my alternator was replaced not long ago. I wish that had been my problem. A weak aftermarket regulator sent me on a wild goose chase that started last Fall.

 

It's been more than two months now and the NOS OEM regulator is still flawless.

 

Yay!!

 

Goody Goody!

 

Now I think my AC compressor might be going. It's the original compressor. Sounds like birds chirping upon starting the truck. Goes away in about a minute. I haven't started the truck in 5 days. Not sure that has anything to do with it.

 

Probably just the bearings in the clutch. You CAN replace just the clutch...... just gotta be creative about sourcing one.

 

I can find the bearing on RockAuto. Does it make any sense to replace only the bearing or will the clutch and coil need replacing at the same time? I've never dug into one. My AC is starting to fade too. And being R12 I'll need to do a conversion to R134a. This is growing into a larger project.

 

I think its easier, (but not cheaper...) to just replace the entire assembly. Remove the old one, install the new one, end of problem. Need the special tool for removal/installation though. Don't know if the local parts store would rent one of those, or not. You probably *could* replace JUST the bearing..... but, that clutch has been on there for a lotta years.

 

I'm generally with you about replacing the whole thing. I'm just thinking I may not be able to find the whole thing. I might be down to replacing the bearing only or the entire compressor. One or the other. I'll have to look around. I suppose there are always boneyards.