84 F150 Blower Motor Problem

The fuse keeps blowing. I have taken the motor off and run a jumper directly from the battery to the motor and it turns OK. Seems to have a little resistance but I don't know if it is too much or not. I suspect the problem could be the resistor circuit. I have taken it off and looked at it but don't notice anything wrong in looking at it. Is there a way to check it? Any other advice you may have? Thanks for your help on this! It is getting really cold here.