Hi,
I have a 2005 S40 T5 with a climate system that allows separate temperatures for driver and passenger.
I have had this problem where the driver side vents blow out hot air (as hot as it can get, probably 85f) regardless of what the controls are set to (controls could be set to 60f and you will get cold air from the passenger side and hot hot air from the driver's side).

The first time this happend (about a year ago) I took the car to a dealer in Mt Kisco NY (do NOT go there) and they claimed that they upgraded the software and fixed the problem. But then it happened again 2 days later, and after a couple of days got back to normal. But now it started again.

Does anyone have any idea what is going on?
Thanks,
Daniel

hi there, my wife and I also have this same problem on her 2006 s40. She does not have dual climate control but whenever she turns on the windshield defrost, the system gets "stuck" with either hot air or cold air. Have you been able to get this fixed, we have had Volvo look at it 3 times and they can not "Recreate" the problem and apparently volvo wasn't smart enough keep even logs on the computers. they want us to stop whatever we are doing and drive it to the nearest volvo dealer when it happens again. I also been given the excuse of firmware upgrades which has not fixed anything.
please let me know if you have found anything.
Thanks,
Eric

Volvo was never able to solve the problem (they told me about a firmware upgrade, and in my case too it did not do anything).
Only thing that started working for me was to set the temperature to very hot (matching what it was blowing out and it "snapped out of" that annoying state.
- nx6

Experienced the same problem with the same short term fix. My local Volvo agent reports that a fix is available with a software upgrade to the AC system and has invited me to bring the car so they do this while I wait. Suggest you contact your local "competent" dealer.

Kind regards
Philip
South Africa.

I had this problem with my 05 s40 last summer... went to the dealer and there were a line of s40's with the same problem. they did something to the ecu (firmware) and no more problem for me....

I have a 06 T5 with dual climate control and had the same issue. Took it to the dealer and said the damering motor got stuck and either replaced it or reset it. Once they did it the issue was fixed. Ask you dealer to try that. Hope this helps.

Same happens to me. I had the issue and a software upgrade fix the issue. Seems like if a problem with the S40 in all countries. fast fix for this, via software upgrade (no more than an hour in the service center.