Driver side A/C is blowing out warm/cool air and the passenger side is blowing out cold air

Hi,

The vehicle has duel side climate control, so there are two blend air door actuators (air temp doors). Since the driver's side isn't working, that is where we need to check.

First, take a look through this link. It explains in general replacing one of the actuators. Also, it discusses common symptoms.

https://www.2carpros.com/articles/replace-blend-door-motor

If none of the symptoms mentioned mirror what you experience, then you will need to remove the actuator and while it's out, see if it is operational. If it isn't, replace the actuator.

Here are the directions specific to your vehicle for replacement of the left (driver's side) actuator. Pic 1 below shows location and pic 2 explains how to replace it.

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2011 Buick Regal L4-2.4L
Temperature Valve Actuator Replacement - Left Side (Left Hand Drive)
Vehicle Heating and Air Conditioning Air Door Actuator / Motor Service and Repair Removal and Replacement HVAC - Automatic Temperature Valve Actuator Replacement - Left Side (Left Hand Drive)
TEMPERATURE VALVE ACTUATOR REPLACEMENT - LEFT SIDE (LEFT HAND DRIVE)
Temperature Valve Actuator Replacement - Left Side (Left Hand Drive)

See pic 1

See pic 2

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As far as the part, if you contact a parts store, just provide the year, make, and model of the vehicle and tell them you need a blend air door actuator for the left side of the vehicle. They all have different part numbers, so I can't provide that.

Let me know if this helps or if you have other questions.

Take care,
Joe