Originally Posted by M1ark
Fan blower. This caused your resistor problem last year and now causing switch problem.
Maybe, the weakest link in the circuit always goes first. Blower motor starts to wear, pulls a little more current. Here's the problem. The circuit has the switch controlling the blower motor which is only rated for 10 amps, blower motor is 30 amps max. So you can see how a blower motor pulling more amps is outside the threshold of a 10 amp switch, causing it to melt down. Some switches seem to be a better quality than others and last longer. If the blower motor was really pulling too many amps then fuse would blow. Solution is the relay modification. Install a 40 amp relay in the circuit so that the switch controls the relay and the relay controls the blower motor. I too had melting issues with the blower motor switch, mode switch and the resistor pack going out. Did the relay mod about 6 years ago and no more problems, still using the original blower motor too.