It seems that the last three years I've had to replace the A/C-heater fan speed regulator/resistor once a year. Lucky I bought the $100 resistor from Auto Zone with a life time replacement warranty but that doesn't mean anything when it fails and the fan goes to wide open/full fan speed and you have to order a new one and replace it

I don't know how to track down what is causing them to fail but I'm thinking one thing might be a bad voltage regulator or something that one of you guys might know what I should be looking for?

This is the exact regulator/resistor that I can now replace in less than five minutes but what a PIA to have to order, go get, and return the bad one every year, what besides made in Mexico/China is making them fail now? Any suggestions would be greatly appreciated