Quote
Anybody ever had one break???.


No, but they can leak coolant through to heater core so heater always on.

Quote
How did you fix it???


I just replace, pretty cheap (mostly plastic) and you can usually cross them over to another make/model as it's a simple on/off valve. I find NAPA good for trying to do that.

92 Montero LS 3.0L V6 Auto, Stock, Original owner, 185,800K miles