Water temperature switch will suddenly not allow cold washes or rinses. Warm or hot only (ie both solenoids do work, just not as required). Same symptoms were observed six months ago, solved by changing the switch. New switches are 90$ each! Is this a high failure rate component, or am I doing something wrong? The switch contains a small circuit board, and there is a temperature sensitive resistor in the inlet hose. ( My previous Kenmore was 20 years old, used a mechanical switch and never had a problem: is this progress?)

Since last problem occurred, I've been careful not to change temperature setting mid cycle, but not obvious what if anything I did to provoke latest failure.