98 Riviera climate control problem

My 98 Riviera will blow cold air from the passenger side and it feels like recirculated cabin air (warm) from the driver's side and the two center vents. I've heard this is a common problem, but haven't heard of a fix. Doesn't matter where the temp is set, I can't get any cool air on the driver's side. Thanks in advance for any help.

there is an acuator below the dash that has a [ / ] type door to control cold/warm air. when a new battery is put in, or the computer does a self check, the door sometimes goes too far open and gets stuck. so the air is half cool/half hot all the time. to fix this you can either pull the acuator and manualy turn the door back to the proper set-u,p or buy a new assembly from the dealer or a junk yard. i would try to fix it first. many times just playing with it will get it working again. i'm sorry but i dont have any pics of where it is or what it looks like but its on the driver side below the dash kinda by the gas pedel. mine was like yours for awhile and now its better but not perfect. all i did was run 90* air and turn it down to 65* and back to hot a few times to work the door back and fourth hoping it would correct itself.
good luck
Matthew
p.s there may be a how-to on regalgs.org or rivperformance.com ;)

OK, thanks. I will try both of your suggestions. I will post back with the results. Again, thanks!