Hey guys! The heater blower motor on my 1986 F-150 will only operate on high speed. I'm wondering if it is a problem with the blower motor itself or a switch possibly? Any info would be appreciated. Thanks!

 

That usually indicates a bad blower motor resistor. The high speed does not use a resistor so it works. On the lower speeds resistors are switched in. Or could be a bad switch also.

 

Do you know if the resistor is in the blower motor itself, requiring the purchase of a new blower motor or is it replaceable by itself?

 

Its a seperate part, held to the plenium near the motor with two screws and a multiwire connector.

 

Here is a diagram with instructions:
http://i608.photobucket.com/albums/t...F150heater.jpg

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Well thank you very much. That certainly explains a lot. A picture is worth a thousand words i guess!!!

 

Well actually, that diagram did not describe my truck. After much research and salvage yard discussion, it turns out that my truck has a resistor pigtail in the wiring coming off the blower motor. Where the blower motor plugs in for power also includes this resistor. On my truck this part number is EIEB 14A459 CC. Apparently you can only get a new one by buying a new blower motor because it is made in with the power cord. Unless anyone has information otherwise?