After searching and with some prompting from 84300DT and engatwork, I found what the part is on the firewall. It is the switchover valve for the overboost. Single vacuum port (no hose attached to it yet) and electrical connector at the bottom. As stated earlier, the vacuum hose that is floating free in the engine compartment comes from the black, multi vacuum port mounted to the top of the cam/valve cover. Can anyone confirm this is the proper source?

Until my CD manuals arrive does anyone have the vacuum schematic for the '84 300D Turbo's engine compartment to share?

__________________
Steve
'87 300TD - 132K - Soon 4-Sale
'84 300D Turbo - 122K - Driving
'77 VW Type II - 77K - Restored
'08 250EX Ninja
English Bulldog (Brier) - My best friend. Passed away 12/02/04 while in my arms.