The original drain hoses on each side of the transmission tunnel were a gray color. On the driver;s side it is next to the accelerator pedal. On the passenger side at the same place. They are just drain hoses, that come out of the bottom of the heater/evaporator box and go directly into a hole in the side of the transmission tunnel. If they are original, they are very fragile. Mine disintegrated when I touched it.
I believe there have been some threads on here about them. Try searching AC drain hose

__________________
John
1986 300sdl
1985 380se