Good idea and I'll check it, but this is the second compressor that this problem has occurred.

Worth testing, but can't imagine that the clutch is bad on two compressors unless we are talking one compressor at 162,500 miles and another one now.

When it does this, can you drive it around or let it sit for a day and see if it resolved itself?

Separately from that question I'm also wondering if the compressor relay is going bad.

It never resolves itself without undoing the negative terminal, and it has done this for many years, so I'd think if it was the relay it would have gone bad by now. This is weird.

Ah, many years. Good to know. Agree this is weird.

If there's a relay just like your AC compressor relay I'd swap them and see if the issue goes away and/or if the issue crops up on whatever you traded with.

Barring a better theory this one's worth a try.

I'm going to replace the compressor this weekend and I"ll do that at the same time (just to see).

If it's making pressure you are likely wasting your time and money. I would look at the expansion valve or condenser. Need to use an IR thermometer and see what is going on with temperatures.

Did we ever get around to testing the coil itself? I'm sure a few of us are curious about those numbers.

I tend to agree, I wouldn't change the compressor based on what I see here.

If you are going to fiddle with relays anyways, may as well fiddle with them first before changing compressors again. Swapping relays is way easier than swapping compressors.

Personally I can't imagine a way that an electronic event while the vehicle is off would change in any way the behavior of the cooling system, except for the possibility that the compressor clutch is part of the problem. The compressor clutch can not be part of the problem without a relay involved. In my mind, replacing the compressor will only add yet another compressor to the symptoms, further proving that it's not a compressor and/or compressor clutch issue.