Now that the good weather has arrived I tackled the no heat on drivers side problem. I first cut the centre console (see photo, you cannot see the cut unless you lie on your back under the steering wheel) I then took off the black cap on the motor. I then unplugged the cable from the motor. Then I unscrewed the three mounting bolts and inspected the motor and cam. The cam has two raised buttons on each side where the problem linkage fits onto. I then drilled a small hole through the centre and made up a pin using a flat headed felt tack!, making sure that it was a tight fit in the hole I had just drilled. I then reconnected the steel linkage then fitted the plastic linkage onto the raised buttons and pushed the "pin" from the back through the drilled hole. You can do this when the motor is loose. After a bit of fiddling around, the "pin" fitted nicely. After refitting the three mounting screws and refitting the plug, I then tested the fix. After 2 weeks the fix has been ok. I exercise the motor every time I go out and the pin and linkage has stayed in place.
http://i439.photobucket.com/albums/qq119/drooscott/FILE0075-1.jpg