climate control freak out

[dna316]

2005 S60-R Auto
Ok so a few weeks back i drove a buddy to the store and we had the heat on but the passenger side only blew cold air. I tried turning the temp knob to cold and back to hot but nothing happened. We parked, went into the store and when we got back in the car all was fine, blowing hot air on both sides.

Then a few days later I was driving to work and noticed that the driver side was cold and the passenger side was hot.
It sorta picks sides whenever it wants.

Then I noticed that when I turn the knob on either side from hot to 60's there is barely a temp change in the air out of the vents, its only when I turn it all the way to cold "blue dot" that it comes out cold.

Last night i noticed that when the climate control doesnt work " only cold air" that i cannot switch to the upper air vent, the one that pushes air to the windshield.

I have made sure to blow out the dust from the air temp vent.
What else can I do?