My wife's 2014 RDX has been blowing hot air thru the driver's side vents when operating the air conditioning--the passenger side works without issue and is cold. I swapped out the driver side blend door/air mix motor this morning, and the AC finally pumped cold thru the driver side. However, a few hours later and it's back to blowing 90° air when on lowest AC setting. I looked at the actuator while controling the temperature dial, and I could see the gears moving in concert to the temperature control changes. Any thoughts/ideas on what could be happening and how to fix?

 

This is a long-standing issue: everyone knows that when the passenger side is cold but the driver's side isn't, it means the system is low on Freon by 200 grams.
I also once argued with people until I charge the freon.

 

Yeah, most likely low freon.

 

Ditto. Probably needs a recharge. This does mean there's probably a tiny leak somewhere, but I would just recharge it and see how long it lasts.