I have an AC problem on a 2010 imprezza

[Ohioufan]

The air blows out of the vents just fine, but the driver side vents do not get cold like the others. What can cause this to happen?

[gbhrps]

Ohioufan,

If you have cold air at the other vents but not the driver's side, the flapper door for the driver's side has either broken/stripped its gears or disconnected from its levers, or the door actuator, if motor controller has failed.

You failed to tell us what trim level you have, or your car's mileage, so I can't be specific. Do you have manual HVAC or is it Automatic, which makes the difference between cable driven/vacuum driven or motor driven output/mix doors for the HVAC unit for that year.

In some cases you can get to the flapper door/cables/motor from underneath the dash. But some require pulling the center dash vents/radio and HVAC control stack, or even the entire dash to get to the flapper door mechanism to fix it.

Your fix could be very simple .. or very expensive depending on the system in your car, and the placement of its various flapper door mechanisms. From just the way you have asked the question, I can tell that you know little about car systems, so you should seek the help of a good independent mechanic to solve your issue. And he can get used parts from a wrecking yard if you need them. Dealership labour rates and the fact that they will only install new parts may bankrupt you on a fix of this nature. Good Luck!