Fan switch is not working at 3 speed. Does anyone know what this might be from?

 

blower motor resistor

 

100% what Scorge said. Coincidentally just replaced mine today for the 3rd time. 1st two aftermarket but replaced under warranty (thanks Amazon) then this one I said screw it and spent a few extra bucks for the Motorcraft. We'll see how long it lasts. At least mine would only blow on the high setting in the nasty heat wave we're having.

* part # Motorcraft YH-1715 if interested. $25 on Amazon.

 

I used a dorman in mine 2 years ago.. still working good.

 

Have same problem as otto man. Replaced fan blower resistor with new motorcraft part. Still have same problem. Could it be the switch itself? Thanks in advance.

 

Yep