zeeth2800

hey guys so i have a 86 yota pickup and my first problem with the heating system is that the switch to turn the heater or air on only works when it is on full and nothing in between. what switch or sensor would that be.

2nd is that my truck warms up but nothing comes out the vents or defroster. what would that be?

thanks for your help everyone.
im a newb i know but no flaming please

abecedarian

for the fan, could be the blower resistor:
http://www.4crawler.com/4x4/CheapTri...BlowerResistor

for no heat at all, even when on 'fresh air' position, may be the valve on the heater hose or the hose / piping may be plugged preventing coolant from circulating.