i have a 91 ranger 4x4 a/c and the heater motor will not work. it used to work on just high, then it just stopped working. i changed the heater motor and it still doesn't work. my old man said it might be the resistor, but he's running his truck without one and his heater motor still works. could this be a resistor problem, or is the switch bad?

 

It's possible to have one element burn out in blower resistor and still have it function on certain speeds. Sounds like that is what happened to you initially. When it gets totally fried you get nothing. If you ran 12 volt direct to blower it would function on high without resistor. Your old motor was probably fine just needed the resistor. Check fuses to be sure that one powering blower didn't blow, but regardless replace resistor.

 

Justforkicks: Your first problem with the blower only working on high is what they do when one element of the resistor pack goes out. Then the other part failed and left you with nothing. Replace the resistor pack and you should be good again.

 

well, i just disconnected the resistor, and now the blower works again. i'm pretty confused by this now, but i guess i'll just roll with it for now. thanks guys, i'll buy a resistor for it eventually. i only have high with it but i live in upper michigan so that's all i need for the winter.

 

why would you get a new blower without putting the old one to 12V first

 

because i was almost positive that it was the blower that was gone because it was one that was rigged in there. also, the blower wasn't the right one, so i figured that i'd get the right one.