[RichMason]

The heater motor is in the engine compartment. You can hear it when the engine isn't running but the key is turned on (and the lever is pulled up). If it doesn't come on check your fuses and relays. A I understand it, these motors can also just freeze up from disuse but this can often be overcome by sticking your fingers (with everything turned off!) into the motor and turning the fan to get the bearings moving again. As pritchard pointed out, the system has to be in great shape to really generate heat and it will always work best when you are taching 4K or more. Good luck!