AC resistor set failing
 

I have a '99 Sebring Conv and am having trouble with the blower motor. It only runs in high. I've replaced the resistor pack twice which fixes the problem, but what is causing the resistor pack to fail? The original lasted 6 years, but the last two only lasted a few months. The dealer exchanged the last one under their parts warranty. Now it doesn't look like the problem is a defective part, but something else in the car. Any help?
TIA
Pete

RE: AC resistor set failing
 

blower motor is over heating and the resistor is the first to go
I live in the atl area let me know