For the past week I've noticed a problem with my heat in my 05 S40 T5--my settings for my heat are on "Hi" but hot air is only coming out of the two vents on the driver's side. The passenger side vents have cold air (as in air conditioning cold.) I've closed both of those vents, but I feel like this could be a problem. Anyone have any ideas or had anything like this happen to them??

 

This is a common issue. The servos get out of sync and the dealer needs to recalibrate. I believe there is a software update to fix this. In any event it is not DIY and needs to be taken to Volvo service.