Truck has not been used for over 2 weeks I think my thermostat has failed because of this. When I came home from work one evening, I noticed that my thermometer was not reading, my fans were on. Even when I parked the truck my fans stayed on, waited 5 minutes and still on. I didn't want to find out how long they take to turn off the battery or possibly drain it, so I just unplugged the battery. Replaced thermostat and coolant temperature sensor, no more problems after that. I will keep youโฆ