The resistor is on top of the box and is held in with two screws. The blower motor wires plug into it. There isn't much room to work...you might not be able to get to it without removing the heater box...I'm not sure. If it's bad, you'll most likely have to find a used replacement. The only other suggestion would be to contact JS Restorations. Jim might be able to come up with something that will work for you.