How to replace blend air door, in 05 Impala on passenger side?

Temp. blend door actuator is probably the problem .
How to Replace DRIVER Side Heat Door Actuator Chevy Impala 2006 2013 DIY

There is a bad blend door motor or controller/wiring problem. Worst case scenerio is a bad blend door within the HVAC assembly

You have a problem with either the blend door actuator of the door itself.

could be a problem with the blend door for that side

I'm having the same problem except on mine it's the driver's side that's blowing cold. Do you have the pictures in a finer resolution? I can't make them out and when I zoom, they are too grainy. Does the replacement require removing the dashboard? What's the general cost of the acuators? Are they readily available at like NAPA or other parts stores?

There is a motor that controls the blend door for the driver's side, that may be faulty, or you may have a stuck or broked dr side blend door.You can access this part by removing the dr side underdash panel, and the dr side knee bolster.

this problem is caused by a sticking air temperature control blend door actuator or blend door, this door moves back and forth to get the desired temp, the actuator is electronic and prone to this type of problem, suggest u replace it.

Blend door mixes hot and cold, not a distribution control. Look for loose or dislodged vac lines... Heater designed to fail in defrost mode.

If you have good heat on one side, it can't possibly be the the thermostat. Good heat on one side means that there is plenty of hot water (water and antifreeze mix) circulating through your heater core. The thermostat controls the temperature of the water. If you have hot water, the thermostat is not at fault. Your Impala is equipped with what is called "zoned climate control". All the inside air (both sides) is still heated by the same heater core. The difference between a "zoned" system and a conventional system is that there is more than one "blend-air" door insided your HVAC housing. The blend-air door swings back and forth to direct the incoming air either through the heater core (for hot air) or around the heater core (for cold air) The drivers blend-air door may be broken or the motor that moves the blend-air door is malfunctioning.

does it have duel cliamet controlle . if so replace right side blend door motor