Heater blower and AC issues

It will also turn on if you have defrost selected with the AC switch off. That is so the system can dry the air and prevent interior icing.
If you do not have defrost selected and the AC is off but the AC compressor is still turning on then my first item to check would be at the AC clutch relay. It receives power through the same fuse as the wipers. If you remove that fuse and the compressor stays engaged the relay is stuck closed. If however pulling the fuse shuts it off, your issue then is either in the switch itself or in the wiring. This is the only schematic showing that system.

Have you had any luck finding the problem?

OK, just checking. Merry Christmas if I don't hear from you before then.