Well I found the problem about why I was geting such erratic behavior from my heat and air conditioning system. I took the Temperature Control Module out and then carefully disassembled it. Quite a tedious task if working without a manual. I removed the control wheel, the button covers and the top circuit board and discovered that two of the pins for the reostats (one pin on the heat reostat and a second pin on the air reostat) that are controlled by the temerature wheel had broken lose from the printed circuit board.
I soldered the pins back onto their circuits and the system now works as well as the day it came out of the factory.
The trickiest part was removing the wheel. It is held on by a plastic axile that looks like a flat head screw but it is actually a groved pin that slides out rather than turn out.