Jeep Repair: ac heater blower not working, blower motor resistor, jeep wrangler

Question
I have a 2000 jeep wrangler.The blower motor for ac heater will not turn on.I have checked power with the key on have power at motor.So I put 12 volts directly to motor it turns on.Dont know if it is the switch or what please help

Answer
From the description of your problem I'd say that the blower motor resistor has failed. The fan will receive power any time the blower speed switch is turned onto any position except off. The fan switch controls the fan speed by switching the path to ground through the resistor. With that said, the tests you did don't make much sense. Applying power to an already powered circuit will not cause the fan to start working unless there is already low power to the fan motor due to bad wiring or a partially blown fuse for the blower motor.