Ac stays on unless you switch to heat.

[steved454]

I have a 1987 K5 blazer, the Ac compressor stays on no matter if I have it switched off or on ac, Max ac, vent or bi lvl. It only cuts off if I turn the heater on. I am thinking it is the ac switch, and not the whole assembly. Has anyone had this happen? trying not to just buy parts for the heck of it.

thanks for any help.