After the engine is warmed up and the heater has been on for several minutes blowing nice warm air the air temperature drops to the point of blowing cool not cold air. Warm air cannot be reestablished until the set point temperature is raised (not on auto). The air blowing out of the vents will warm briefly then falling back to cool. The only way to get continuously blowing hot air is to set the temperature to 90 degrees. Dealer says there is nothing wrong. Setting the heater controls to "auto" makes no difference.
Wednesday, December 19th, 2012 AT 6:56 PM