[W126 Coupe] main air flap is bass ackwards

[Dick Spellman]

Hi Richard:

The vac element that manages air delivery from windscreen to floor is just
to the right of the climate control and up near the dash. Easily accessed
through the glove box cut-out.  That element is a dual unit.  If it
misbehaves as you describe it has a slow leak.  From the sounds of it you
may also have a bad center vent vac element which is located on the face of
the heater box down low and centered behind the radio.  This is the only
element linkage that I can see getting snagged on wiring harnesses
associated with the radio.  All of the others are pretty much clear of
obstacles.  The center vent element on older (pre-1986 or so) 126's is
shaped like a pack of cigarettes and has a small cover to protect the
linkage from snagging.   Easy enough to check and see if the cover is in
place.  You would need to buy a new unit if this has failed as there is no
diaphragm kit.  Keep the original linkage as it is a special piece designed
to fit and run horizontal on the heater box.

Good luck,

Dick