Thought that I would make a final entry for anyone that might be looking for answers. I am sorry to say that I have none. What I can tell you is that it is an electrical problem but a friend of a friend that has had a mercedes shop for 30+ years can't point me anywhere. I finally found a wiring diagram on line but it is totally worthless. Shows all the wires coming out of the control head and where they are going to but no information on what they connect to in the control. With that I just gave up and connected the signal tube for the blend flap to the signal tube for the center vent flap and she has A/C. it has been in the mid 80's in the garage so do not know if it will roll over to heat when it gets cold but if it does not she can just put on a few more clothes. This is Southern California and it just does not get that cold. Benz and I have had our knock down drag out fight and Benz won.