Usually, if the resistor goes bad, the fan will usually run at full speed, or not run at all. In my 2009, I could not find any way to just replace the fan switch itself. It required the replacement of the entire control module which cost about $150 new, or 50-65 used off ebay. I just learned to live with the 3 speeds I had, and that was more than enough. Good luck!!I had a chipmunk get into my blower motor and build a nest I pulled the motor cleaned it and reinstalled but every time I turn the motor speed to 4 it blows a fuse instantly. Speeds 1 through 3 work fine. Is this a resistor problem?
In case it matters it is a 2009