I know the switch in the receiver/dryer is a low pressure kill, but what is the one in the compressor itself? Also, what is the one in the high pressure line for?

Another question:

Do the switches change from normally open contacts to normally closed contacts depending on the year? If so, what years have what.

I have fried several compressors in the last few years and I think it's only when I've been running the 89 computer and adapter harness in my 85. A guy who put my car on a scanner said that the computer was showing the AC as running all the time even though it wasn't on.

I have wiring diagrams now so I can double check the adapter harness that someone made for me about 8 years ago. But I want to cover all the possibilities!!!!

 

The one in the compressor is a high-pressure cutoff. It is normally closed, and opens when the head pressure goes too high. Probably 450 psi or so but I don't know the exact value it's set to.

I know of no switch in the high-side line.

There's no way that "wiring" can "fry" compressors. The compressor either runs, or it doesn't. That's all the wiring can do; is to either send power to the clutch, or not. Neither thing can "fry" the compressor. Sounds like something else is going on.

Exactly what went wrong with them?

 

What happens is the compressor would work fine while going down the highway, but would freeze up and blow the seals during around town driving. If the coolant temperature got anywhere near 230 lookout!!!! Stock; the electric fans on this thing don't turn on until almost 240 so somethings wrong.

I have wired up a 10" cooling fan (behind the radiator) to run all the time. I have a 16" fan (behind the radiator) that will come on at 205 (thermostatic fan switch in the passenger side head). I also have a 12" and a 14" fan in front of the condenser that are controlled by the computer.

Until this time I have always run new compressors so it isn't a cheap rebuild problem.......

Whatever that thing is in the high side, it has wires coming out of it.