Hi mate i have just pulled out my fan motor Very easy to get out 10 min. I had the same problem and after a good inspection i found that the comutator brushes in the fan motor were worn out ( Not the resistor)
Please check the length of your brushes to ensure they are touching the comy. It is a simple process just remove the two screws on the top of the fan motor and the who plastic piece will come leaving you with the motor and fan. You will see two clips holding the brushes in just pry of and check your brush length. The clips just press back on . If you are not sure what the lenght should be . The brushes should be at least one half inche in lenght. YTou may have an auto elect mate who could look for you only takes a couple of mins. Regards Roy