[W126 Coupe] main air flap is bass ackwards

[Dick Spellman]

Richard:

You need to observe the main air flap functions using the Mercedes Output 
test for proper diagnosis of its operation.  Cabin temp if cold will close 
that flap until correct heated or cooled temp is reached then open it 20% or 
so when make-up air is called for.

I do not recall if there was a nylon fitment on the air doors that would 
allow you to 'screw' the linkage in or out on you query re: center or side 
air delivery.

Dick