408 (and others) fresh/cold air ventilation question.

[dwomby]

My car has had the control lever for the fresh air vents removed. The cables to the vents have been cut. The vents seem to be rusted in the closed position. I am wondering how they are supposed to operate. Am I right in thinking the vent opens outward toward the plenum aft of the engine compartment? That they open by the cable pushing them rather than pulling? That the closing flap is not hinged on one side but instead is swung outwards on two pivoting arms and held open parallel to the opening itself.

Any suggestions on freeing the frozen mechanism or am I better off leaving it all as is in case of water entering from the plenum?

Thanks for any help.

David