If the defrost is on, that is normal. The pulley turns as engine runs. Electromagnetic clutch engages to clamp hub late in clutch to pulley to turn compressor.

 

Since I brought the truck home, I have driven it for hours around my home and the problem hasn't occured once. Either the problem is intermittent or reseating the alternator and battery connections took care of it.
Would oxidation on the alternator terminals cause the problem I described?
This afternoon I am going to loosen all the connections in the major electrical system and give them a good cleaning with electrical cleaner and a brush.

Aside from any obvious chassis grounds that I'm likely tto find, are there that are imprtant but well hidden?

Adam

 

Bad/dirty connections could indeed cause your problem.

There are a couple grounds on the back side of the motor, to the body. Clean those good too.

 

I drove the 2500 15 miles to work today. It got me there.

On the way, I had my headlights on because it was raining, so I had my headlights on. During the drive, the battery meter was generally above 14 volts, I'd even say 15 volts. At one point, it dipped down to around12 volts, then jumped back to above 14 volts. A little later, it dropped to 12 volts again. Getting a little nervous, I turned off the headlights and it immediately went back to above 14 volts. If this is an indicator of any possible malfunctions, please chime in.

Adam

 

Sounds like either a poor connection somewhere, or, a failing voltage regulator...... mine stays above 14 regardless of what's on..... gets a bit lower at idle, but, still, always above 14.

 

While it is running take the truck to the parts store and get that alternator checked while under load as well as the battery. That is the proper way to check it. This will help take out guess work. It is very expensive to just throw parts at it. As for me I do not guess and throw. With the voltage going in and out there is definitely all kinds of signs that battery, alternator, and/or VR issues. Do yourself a favor and have that load test done.

 

PFFTTTT. There are plenty of videos on YouTube that show how to test an alternator with a voltmeter.

 

Ok, either way he should test it.

 

There are grounds to the engine block from battery and from firewall, ground to frame below battery box, grounds to fender by radiator support, aan one I found this week.....about 12" below the one on the driver side fender - 8 to 12 wires on a stud, clevery hidden by darkness and windshield washer bottle....

Grounds all over the engine bay!

 

Whoa! When I look out my front door, all I see is ground everywhere as well.

Coincidence?