I have 2004 Mont e Carlo ss, my hot air still blows into the vent when I turn of the heat. I only noticed when I start doing 55 mph plus, could it be HEATER BLEND DOOR ACTUATOR?

 

Where is it set to blow out of when this happens? Face, feet etc. And what is the temperature set at? Once you get up to highway speeds, the air moving across the car will push air through the vent system even if the fan is off.

 

It will blow from any where, my temperature is set to cold. Yes the air moving across the car will push air through the vent system even if the fan is off. Just sucks because it is Summer time, and having hot air blowing.

Thank you