My 79 300SD/116 (almost always) has no heat to the footwells regardless of which button is pushed on the climate control panel. The car holds vacuum well (for days!), so I think a vac-operated airflow routing door is sticking or something. Is there an easy way to rig something that would allow heat to enter the footwells? I suspect there's a way I could just work the door(s) by hand and free it up, but I have no idea where to look! As a matter of fact, I can't even figure out where the footwell airflow is supposed to come out!

The aforementioned (previous post) gal-pal is complaining- and hot air blasting on her face and torso from the windshield and dash vents is not helping. I used to be able to close the center and side dash vents with the levers and squeeze some heat out below, but no more! There is plenty of warm air in the plenum, and the blower works fine, air just won't come out down low. A full repair will eventually happen, what I need now is some info on how to access those doors and/or their actuators/linkage for a little manual "persuasion".

This is a classy beater, not a restoration project. Crude temporary fixes are welcome...

Thanks in advance, Dave Larson