CC doors change position under different acceleration

[glenlloyd]

Don't know how much response I'll get but here goes.

When I have climate control on, actually just vent since the AC is still defunct but EC is not illuminated, the position of one or more of the doors inside the plenum under right side dash will change position under various acceleration rates. If I push the car hard I hear a definite change in something under the right side dash, but when I approach say a light and am slowing down I hear it return to where it was, or at least change again.

I assume this is most likely a vacuum issue that I'll need to tear into and find but I thought I would put it out there for comment before I started in on it.

Unfortunately the W140 FSM is not available on the net like some, and I haven't brought myself to the point of forking over the money for one yet.

I will say that it would appear that one or several people that have worked on this car in the past, before I bought it, should not have, so the problems could be entirely man made and it wouldn't surprise me in the least.

Any help or advice would be great, and if what I've written isn't entirely clear LMK.

Thanks
Steve A