Why does the drivers side panel vents blow hot air when the passenger side vents are cold

Click on this, it will get big enough to see..study it..hopefully it is helpful. Maybe some ductwork is off. There are solenoids, vacuum hoses, all sorts of things. This is specific to your 1999 Park Ave.

every time you replace the actuators you need relearn the system, you can find the procedure on Mitchel on demand or alldata

It has nothing to do with the actuator your refrigerant level is low when it is 6 to 10 pounds low the driver side blows hot on the passenger side blows cold end of story.

Add a can of freon and check. The simplest, most cost- effective first step.