AC vent blows warm only on one side...weird
 

My wifes AC blows ice cold out of the drivers vent, medium out the driver center, warm out of the passenger center and even warmer out of the passenger vent. I searched and searched and I can't find anything. I've changed the FSR about a year ago and occassionaly the ac just stop working for a day.
Tks

heater (water) valve. I just had same symptoms, and it now blows icy cold. The part is expensive as you need the dual climate one (assuming you have dual climate) but the fix is DIY.

Part 1 below.
http://www.realoem.com/bmw/diagrams/i/y/125.png

I had exactly the same thing. Did research on site and found it was diagnosed as a leak by the heater valve like sprockett indicated. When my wife took the X to the dealer I told her to tell the service advisor, but the SA said it just needed a refrigerant recharge. She said he promised to do another charge if it didn't cure the problem. So the A/C is cooler now on both sides, but I don't think it really fixed the problem.

BTW, as I had posted a few days ago, the S/A turned out to be pretty unknowledgeable. After changing out my general module he forgot to reprogram the keys. When my wife brought the X back because her remote now won't work, he found he couldn't reprogram it and pretty much accused her of bringing him a dead key. After I raised a ruckus with the dealership's customer service manager they studied the problem further and found you have to have both keys to successfully do the reprogram. Since he didn't know this little detail I have doubts he knows much about the A/C problem. Oh they also forgot to re-initate the pano sunroof, which has to be done by techs every time the power is disconnected (like a battery change or disconnection for electric service). So my sunroof control was acting up, and the wife was just about to bring it back when I found the instructions for retraining the sunroof on this site. Long story short, I think the heater valve is the right diagnosis, dealer service guys are hit and miss (a lot of miss), and thank gawd for this site.

Could be the heater valve like they are saying, or could be low refridgerant in the system. The easy ways to tell would be to read/analyze the operating pressures and/or pinch of the hoses from the heater valve to the heater core with hose pinch pliers.

Or if when this is happening there seems to be extra water dripping from the ac drains, I'd say the heater valves... if less/no water is draining that normal, probably low.

Well that's good to know. I just drove in up to 104 today in northern San Diego County just to test out the A/C (and hit the casinos)...and the recharge seems to work so far, so maybe it was the right diagnosis in my case.

hey guys,

I was actually shocked that this worked, but i have dealt with my guy for years and trust him. I specifically asked if he touched the a/c system and he said he hadn't.
it is unbelievably icy cold now.

they also found a cracked intake boot and replaced that without me needing to ask.