1987 Ford Truck V8 Four Wheel Drive Automatic 112548 miles
my heater control switch only works on the lowest setting nomatter what setting you move it to. I replaced the blower motor, thinking maybe somthing was wrong with it from advise from a backyard mechanic. Could you please point me in the right direction on what to do next. Thanks for your time.
Under the hood disconeect the heater motor connection. With a static light chec to see if there is a difernce in voltage when the switch it turned up or down. If no diference check the fan switch control under the dash.