So the issue is self explanatory from the title but I’m not sure where to start. This is happening whether the system is set to recirc or not. It’s outside air getting in and I assume it’s a flap door stuck but I don’t know where it is and solutions. I assume it’s a motor that has gone bad. Any help would be appreciated.

 

When in the winter time if you use Auto it will normally make the upper vents cooler and the lower foot position vents warmer to prevent it from fogging up the windows. You can turn off the AUTO function and you can also enable ECON which turns off the HVAC compressor completely. To verify the heater core is good pop the hood and feel the in/out heater core hoses. They should both be warm. If one is cold and one is warm = core is blocked.

Summer it could be low R134A, and make sure you have the RE-CIRCULATION button enabled for the most cool air, and make sure ECON mode is off. Checking the flaps themselves is kinda tough, but you can lower the glove box and cycle thru the modes and listen to them and feel the air change places. If you had a flap truly stuck you'd have a good amount of air flowing out of the vents with the HVAC system totally off.