Hey Thomas,
I had the same kind of troubles. I didn't want to fool with replacing the climate control unit since it seems like such a nightmare! I disconnected the control unit's cable that attaches to the heat/defrost door in the plenum. If you look behind and to the right of the cigarette lighter area on the dash, you will see a cable connected to a control arm. You can disconnect the cable, and then when you want heat versus defrost, just reach behind the dash and raise the control arm. I know it's a redneck fix, but it works! At least it won't cost you anything to make it work. The only problem is that the fan has to be set to the 2 fastest speeds to keep the door in the heat position.
Have fun,
BigDonkey