89restoration

It reads "off,vent,bi level,heat" I can't get to it right now as its 11 pm so I can check inside the engine tomorrow for a compressor

I have a Sport Truck trim and it is from 1989. I am restoring this truck and my dad claims it has a heater but no ac instead he says it has a "fan". I can't seem to find anything about this,but many questions I've had have been answered previously so I was hoping you guys could help out. Thanks in advance