I've gone through a fan speed switch every couple of years. They've locked in high, and melted and just plain didn't work several times. My wife likes to have the fan on high whenever she drives. (She's a smoker). It seems the high current coarsing thru their little conductors tends to heat the pretty good. On the up-side they used to be like $35 each! I think the last one I bought was around $5-10. They're easy to replace, too, fortunately.

Thomas Brobst
Accu-Sort Systems, Inc
Staff Mechanical Design Engineer
215-721-5061
fax 215-799-1600

It has yet to be proven that intelligence has any survival value. 
--Arthur C. Clarke