My Ford Focus 2002 heater resistor pack only lasts a couple of weeks?

have you tried lubricating the motor bearings? if the motor is a bit stiff or if something is jamming it, it will overload the resistor pack & the switch & anything else associated with that circuit. as for the fuse, it should already have one in the fuse box, check with your handbook to see if it has the correct one fitted.

jim
January 2010