This question has come up before,the answer will be probably one of two faults. The switch itself can be faulty,it "feels" ok when operated but is not passing current.Or,the resistor which regulates the fan speed as selected on the switch is failed.There is a full answer on the site about how to replace the resistor which is found usually in the heater ducting under the bonnet.
Go to an auto parts store and ask them to link up to the Jeep's computer.
If you have checked the blower motor and it does function when power is applied then I would suspect the Blower Motor Resistor Pack is defective. It is also possible the blower motor speed control is bad, but highly unlikely.
my infinity g-20 blower not working
Possible causes could be, fuse, relay, sensor, blower motor or electrical connector.
Check the blower motors ground and power in the truck and the blower motors resister......
have you checked the fuse if so then you will need to replace the resistor for the blower hig and low dettings have you checked the fuse do you have 12 volts to blower if so then you will need to replace the resistor for the blower replace the blower motor
Have your blower motor resistor or blower motor checked out
crown Victoria blower not working and head lights.
The blower motor can be checked with an ohm meter to test continuity. Also, use a volt meter and check to insure that the resister and motor are actually getting power. a broken wire or bad plug connection will cause loss of power.
try replacing the chip that's located in passenger side under glove box and is in the heater vent which goes from the heater blower to the matrix cover hope this helps i changed mine and all was well.
Have you checked to see if your 12V dc relay under the hook is working properly?
If the blower motor is not working, it is either a blown fuse, bad bower motor speed control, defective blower motor, or more than likely a bad blower motor resistor pack.