Your way and mine will proably be different. We would probably install a known good switch to make the determination as it is so easy and we stock them.
To do it a little more professionally you will need a wiring diagram. I usually determine the two wires that go to the motor (direction of travel is changed by reversing polarity). I then locate and verify the B+ and ground wires. Then I manually jumper the B+ to one motor wire and the ground to the other. This is what the switch does. The motor should go one direction or the other. Just be carefull that you aren't going down when the window is already down or vice versa. Make your final connection temporary (just touch it to see direction).
Owner 24 bay BSC
Bosch Master, ASE master L1
27 years MB technician
[This message has been edited by stevebfl (edited 10-23-2000).]