I scanned the manual for the 81 D/CD for the left front switch/motor wiring. Here's what the MB manual says: Wiring to the motor is sw (up) and gn (down). SW connects to pin 3 in the switch, gn connects to pin 4. Power comes into the switch on pin 5 rt. Is this how the switch is setup?

Color coding
sw-schwartz (black)
gn-grun (green)
rt-rote (red)

Sorry about the spelling of some german terms my memory is fading.