A lot of fan units, have a resister network built in to them, for speed control, could be that, Or could be brushes on the fan motor worn out cheap and easy to fix yourself, as it does not work, take the fan unit out, and test, there is a pcb inside, which is the resister bit, but usually another plg unit goes to the motor, disconnect that and test with meter, if open cct, brushes had it, cheap on ebay, or resister pcb, again cheap on ebay I assume you have checked for any fuses.
SD, February 2012
