I have a 2001 LeSabre. This winter the driver's side had hot air, the passenger side had cold air. Since the car was not being driven I figured I'd worry about it in the better weather and I'd have plenty of time to find the problem.
Today, I found that even when set to a low temperature, the driver's side still has full heat the other side still cold. I'm guessing a damper is stuck or an actuator is not actuating. The temperature remains the same on the respective sides on floor, mid, and defrost. Is all of that stuff under the dash? I don't seen any access to anything from under the hood. My body was not designed for working under the dashboard these days either.
If the Cash for Clunkers goes through, this car is a candidate for replacement.