blower motor works on high only. 2000 jeep cherokee. lower speeds not working

blower motor resistor may need to be replaced. resistor module is located in the heater box next to the blower motor. The glove box may require removal to gain access the the resistor module.

Twice I found mice! Pretty good rhyme, but it's true. Both times, twice in 5 years mice got in under the firewall and drug all kinds of matting lint, etc and eventually shorted out the lower three speeds. The last time (2015) no speeds worked.