Hello, I own a 2002 V70 base w/140K. The car has manual A/C with knobs, not ACC (Automatic Climate Control) with the 3 tier silhouetted man.
Lately my working A/C has been shifting between putting out cold air and hot. I've done a ton of searching on the Volvo boards and this particular symptom came up only once. The suggestion was to turn the temperature controls rapidly for a minute to loosen any dirt. The air temps fluctuated as I did this but solid "cold-to-hot" control did not result. Are the temperature controllers electronic encoders? I assume they're not connected to valves or cables. My next step will be to gain access to the back of the panel and spray electric cleaner onto whatever I find behind the knobs. I wouldn't think the blend doors are sticking. There's no noise. I will lube them, as well as any pivot point, when I see them. Are there vacuum hoses which can deteriorate in these systems?
I believe I start by removing the pen holder by pulling it out straight. Screws will be reveled and the control panel pivots out of position. I've read warnings to leave the panel plugged in. The SRS light can come on if I unplug it.
Does anyone have any experience with this kind of problem? Thanx, Kira

Hello, After working the pen holder loose you'll find 2 Torx 25 screws. The bottom of the A/C control panel pivots out and the top edge pulls straight out. I made a small 90 degree hook out of scrap metal to pull with. Remove the 7 small phillips screws and work the back off the control panel. It's really a box. The back has holes for the 2 plugs so you don't risk unplugging the unit to do what I did. The electronics are revealed when the back half is worked off. I assume the temperature controls are optic encoders. I shot them with common electronics cleaner. More dirt came out than I ever expected. The controls are responsive now. I have no way of knowing if I was successful or merely coincidental. An unlucky few have caused their SRS light to come on by unplugging the unit. Fear not if you need to do this. Kira