[DmaxDually]

Yeah, I was surprised the dealer had the part in stock for my truck. I don't know, but to me it seems that owners in the cold weather States have more DEF issues because of the heaters. The heaters seem to be the weak link. I live in FL and this was my 1st DEF issue since new (7 years and 118,000 miles) and it wasn't the heater. It was the temp sensor. I don't think my DEF heater has ever been on. I don't know how hot the heating elements get but maybe it crystilizing or cooking the fluid which causes all the issues. I'm guessing the heater comes on even when the truck is parked and the ignition is off so the fluid doesn't freeze over night.