ok, sometimes when my fc(86) warms up, ill have the slider set to hot, and turn the blower up all the way. when the heat isnt working the blower will blow quite noticeably harder and sometimes i have to turn the car off then back on and the heater will start working. but sometimes it doesnt, its quite annoying at times. and idk if this helps but when i turn the blower on full something in the engine bay will start squeaking. its not crazy loud but i can definetly hear it.then when you turn the slider down to off, it goes away. and before someone asks......yes the ac switch isnt on.

 

Logicon could be failing. Or the electric valve that controls coolant flow into the heater core could be failing. Squeaking noise could be the blower motor itself. Can you only hear it when outside the car? The whole blowing harder when it's not working also may point to the logicon failing. It may be putting the car into recirculation mode instead of in fresh air mode.

And for the record I've got a slightly different problem. I've got heat all the time. Perfectly working AC but I can never use it since I'm always on full heat. Pretty sure my heater control valve has failed open.

 

what is a logicon? im still brand new to the rotary world....and to be honest ive never really messed with heater/ac issues before. how does one go about troubleshooting this issue