Some car heater fan motors are mounted on the engine firewall, and can be accessed from the engine compartment. Those can easily be tested with a voltmeter, to see if the motor is getting power...if so, the motor is bad...if not, the circuit/fuse is bad. However, if the fan motor can only be accessed from inside/under the dash, the labor costs can go up quickly, and a dealer is your best repair option, because their mechanic will probably do a faster and better job. At any rate, if you live in a colder climate, not have a working heater in the car makes for miserable...and sometimes unsafe....driving.