It’s been way too long, but many years ago, I remember selling a bunch of GM A/C fuses. It was not a normal fuse, it seems like it was about 1 1/2” long black rectangle.
AC is an area I’ve never been that strong in.
Between meters, test light, wiring diagrams, and some testing, I’ll see.
It wouldn’t surprise me if there was an oddball fuse like that in the system.
Thanks for the tip.