Is this the cruise control module? If so - does anyone have link with a diagram that shows me where/how to route the "missing" tube(s)?

 

There should be a vacuum hose coming off it, going into a tee fitting. One goes to your brake pedal and the other to a vacuum pump. I know on a D1 it is under the jack on the drivers front, but I think on a D2 it is passenger side closer to the firewall

 

No t fitting - no hose either - other than the 1/2 inch broken off piece still attached to the device in pic 1.

 

There should be a switch on your brake pedal. Feel up the arm of the pedal. one is electronic, and the other is for the hose. Follow it out through the firewall and see what it is connected to..