Greetings. I just bought a 1990 Legacy AWD wagon. The A/C usually doesn't work when I switch it on. Sometimes nothing happens -- no blower nothing. Sometimes air comes out of the upper vents, but it's not cold. Sometimes cold air comes out, but only from the floor vents. In all cases, if I bang on the dash a couple times, it will usually start blowing cold air out the upper vents. The air is pretty cold, so I think the A/C is ok. Seems like a switch or connection or something to me, but I'd be grateful for any advice. Is it a nightmare getting to it, if I have to replace the switch or something? Thanks, BK