Air Conditioner

There are two types of mode door actuators. One uses a computer with electric motors. The type that often develops your symptom uses vacuum motors with mechanical controls, typically push buttons. If that is what you have, look for a broken or disconnected vacuum hose under the hood. They are usually small hard plastic hoses with a small check valve near the firewall.

Vacuum-operated mode doors are spring-loaded to default to the defrost position when there is a problem with the vacuum supply. That is done for safety. Your feet might freeze but your windshield will be clear.

Yep some dealerships are poorly run for sure, If one vent is cold it means the ac is working fine and it is a climate control issue. Did they replace the correct blend door actuator, seems like they did the wrong one?

Hi guys. Sorry to say I'm the wrong person to get involved with heater boxes and actuators. Those are kind of a specialty area for HVAC, (heating, ventilation, air conditioning) people.

I did want to add one comment though. We had a very high-level trainer travel to our community college once a month from another state, and in one of his presentations he said as far as having "customer-friendly business practices", meaning looking out for customer satisfaction before profits, the top three in the world were Hyundai, Toyota, and Chrysler. At the bottom of the list was GM, BMW, and Volkswagen. Hopefully that will make you less upset with your car even if the mechanic didn't fix it right the first time.