Originally Posted by
NumberDummy
81-F-150-Explorer: There is no "mode" switch (19B888: A/C Temp Control Selector Valve Assy) since there are no vacuum motors that control these two damper doors.
The cars used it, but the trucks didn't until 1973.
No, not that switch. There is a electrical switch that turns the A/C on and off depending on where the function control lever is placed. On with the lever on A/C and off on all other functions, Floor, Defrost, off, etc... I had problems with that switch on my 1972.
Would only be a problem if the A/C works. It being on and cooling the air the heater is trying to heat up.
The heater only assymbly can be swapped in place of a broken crusty factory A/C unit pretty easily.
