My 81 has the same problem. Behind the knob the attachment point for the cable that controls the flappers for the airflow is plastic and can and will break. That leaves the knob free-wheeling. I have found out that you cant buy just the control knob and need to buy the entire dash part that includes the other two knobs, air cond vents etc. I got a price of $195 from the dealer. Needless to say since I live in Tucson it is not a high priority. I would be interested if someone has one in good shape at a greatly reduced price. As far as the blower bird living under the hood, I think they come standard on this model.

Another minor but annoying problem: whenever I turn on the blower and left it on position 1 or 2, it started to squeak like there is a little bird living inside the dash. It goes away when I turn the fan speed full blast. Any suggestions where to lubricate. Thanks.