One cold morning getting ready to take the kids to school, noticed heater was blowing cold. Checked and made sure switch was turned to heat. It was. inadvertently discovered later that turning it to cold actually blew warm air. Have replaced radiator, thermostat, water pump, and tried to reset the switch per a bulletin I found, to no avail. The worst thing is, when it blows heat, if I turn the fan to 2 or higher, it stops blowing warm. Checked the inlet doors and fan housing. Flushed heater core... nothing!