My a/c just started doing the same thing. Blowing hot air through the drivers side, and blowing cold air through the passenger side. Open the glove box door and there are three 7mm screws that hold the glove box liner in. Two on the left side and one on the right that also holds the door strap in place. When you pull the liner forward, use a flathead screw driver to disconnect the trunk release button socket. Pull the liner all the way out and set it aside. (Also a good time to clean that mess out of your glovebox!) As you look through into where the liner was, you'll see up on the left side, the actuator that controls the door for the right side a/c or hvac. ( If you look straight, on the right side, you'll see the acuator that controls the defrost door.) There is an electrical plug that can be pulled loose with just your hand, located on the bottom of the actuator. There are two 7/32 screws that hold the actuator in place. Remove those and the actuator should pull free. I took mine out and opened it to see what I could see. The gears were fine so, I thought maybe the little motor was bad. After I took a picture of how the sprockets were positioned in the motor, I took the sprockets out and set them aside. I then took the actuator with motor back to the car and plugged into the connector. I then turned on the a/c controls to see if the motor came on. It did. So, I am wondering if the motor is weak. I am going to put it back together and see what happens. If it still doesn't work, then I'll put in a new motor.

The time that it took me to take out the glovebox liner and remove the acuator was about 3 minutes. Shops and dealerships that charge hundreds of dollars to replace this particular actuator are ripping people off. I can see maybe charging an hour for removing and replacing it but, not more than that. I don't know how much the part is yet or if reinstalling the old one will fix the problem but, I'll post more on this soon so, check back. I have posted a couple of pictures of the actuator I took out of my car.