About a month ago I had the notorious single speed blower motor on my 2003 F150 XL. I replaced the resistor, which was very rusty, and everything worked perfect. Today I get in and I have no operating blower at all nothing Where should I start looking?
Thanks, Mark

 

I would go back an check the resistor and its connector. If that's all good start checking fuses. I always like to start at the place I worked if stuff messes up, because auto part stores always sell awesome quality stuff! Haha

 

Thanks for the quick response! I started moving wires around down near the resistor and started getting intermitent operation of the blower. I discovered a wiring harness (the one that plugs into the blower motor and into the resistor) It appears to have a short in the plug where it plugs into the blower motor. Going to order a new harness tomorrow when the dealer reopens.

 

Check your blower motor. It is probably on its last leg, drawing a lot of power (resistance) which will tend to melt some of the wires to it. That could cause the resistor to go bad. The motor probably has a load of dirt and material from the brushes inside.