I have a 1991 300d and have issues with the pass window rolling down. The switch is good. The motor has power at both posts and when I removed the regulator/motor it worked both ways. The window only rolls up! When I switched the posts it only rolled down. I dug deep into the forums and can't find an answer. I also tried tracing the wires from the switch to the motor and found A LARGE CONNECTOR with nothing connected in the place where the factory alarm control should be underneath the pass side dash on the floorboard/ firewall.
Could it be that the previous owner removed the alarm control or did some models not come with alarm control box? If they did remove it, could that be the reason my window won't work?
I looked at a 1990 300e gasser set up at the wrecking yard the other day and realized where the mystery open plug on the left side pass foot well connected to, but I didn't have the pug on the other side close to the door that is mounted to the floor and red in color. I'm confused and am desperate!