Ok, this is for a 1992 300D 2.5 Turbo euro headlight. They do have the vaccum controlled up/down level option for heavy or light loads. But I need to install the vaccum lines on the car and the switch.

On page 78 of the STAR July/august 2000 issue, it says "Your vacuum source will be the economy gauge line, which you pulled off the back of the instrument cluster. Install a tee in that line and run the new line to the level control switch, whith a check valve...If your car has no economy gauge, use anotehr convenient vaccum source."

Obviously I do not have an economy gauge, so what is another "conveint vaccum source", that I can use?