nice avatar... I'd love a BMW sign like that

 

It happens to mines too. Did u find the problem.

 

I had mine replaced at the dealer under warranty. A friend with a 535i had the same exact issue and also got it replaced at the dealer.

 

I just fixed this issue by taking the whole ac controller apart and having some thin foam near the knobs. The controls are loosely house. I also rebent the contact points. So far so good my ac is now not turning on itself.

 

i was under the impression that this was caused by our automatic climate control systems. i.e. the climate control was sensing too much or too little humitdy etc. Boy was i wrong.

 

^^^yep, have/had the same problem. i now just keep my fan on the lowest setting and turn the a/c off by pressing the snowflake button.

 

In the manual it says cool is turned on when you are in auto mode. See "Switching Cooling On and Off" section. Page 117 in 2009 manual. It is done to avoid condensation.

 

This happens to my car, too. Noticed it just recently because I never run the heat since I live in Florida, but during winter months I do turn off the system every once in a while. When it turned back on twice, I thought my car was possessed.

 

Go into Idrive and turn vent settings off. When you need the Air hit max button. Worked for me

 

All I have to say is F*** the A/C Knobs, that is all.