AC cold air blows out the passenger side vents but hot air blows out of the driver side. It is easy to tell that the air on the passenger side is cool and is conditioned air. Flapper valve of some ty

Could be the motor that moves the doow for the drivers side. Is the hvac control digital or manual. If its a manual one there is a possibility its bad also. Get a repair manual and follow the steps for repairing.

It is digital. Where do I find a repair manual? I thought it might be some kind of damper that changes air flow direction. You seem to agree. How difficult is this going to be to repair?

Any auto parts store should carry a repair manual if its digital and the readout shows its set to minimum then the chances of it being that are lessened. There are servo motors that control the flapper/blend doors. They generally aren't too bad its just in an awkward place. You will probably have to remove the panels under the dash and usually that will give access. The repair manual will give more specifics.