Do a search for a thread started by Gary F. entitled center AC vents not working (or close to those words) dated 3-21-02. GSXR wrote that on his '85 300D the switchover valves are located where I described them - behind the control panel (the device with the push buttons to control fan speed and temp). When looking for info about the AC system, you should be more concerned about general info because the various sub-systems (the valves, actuator, switchover valves, lines, etc., etc.) generally work the same way, it is where the sub-system components are located and accessed that is the particular problem you have but may be fixed by another member's way to fix their particular sub-system. Am I making sense to you?

M-B is bad about not showing where components are located in the "official" service manuals. The M-B dealership techs get that info in service bulletins not available to the public (trade secrets).

Good Luck!
Tom

__________________
America: Land of the Free!

1977 300D: 300,000+ miles

American Honda: Factory Trained Technician & Honor Grad.
Formerly:
Shop Foreman;
Technical Advisor to Am. Honda;
Supervisor of Maintenance largest tree care co. in US for offices in Tex.