Hey guys, I recently replaced the heater core in my 1977 Datsun 280z and when I went to switch the top level (from ac, to bi level , to heat, to defrost), the switch felt rather loose and it didn't seem to switch anything. It opens the two bottoms doors (below the heater core), but does not seem to do anything else. I believe something is not connected but I can't seem to find out what. I'm really frustrated, and just want to figure this all out. Thanks John