You will need a test light or a cheap digital meter. To check for the supply voltage etc. There are two electrical circuits for the windows I believe. One circuit does one front door and one back door. The other circuit does the other front door and the other back door.


It may be helpful for you to get a wiring diagram. If there are two fuses for the window circuit you know you have the dual circuits.


I also could be wrong about my description of the electrical setup. Others will correct that if I am. Just as a guess it sounds like you may still have some wiring connections mixed up. If you have no electrical experience and it where possible to look at the connection order of another car I might take advantage of that. Even one in a wrecking yard. I had a quick look at a manual.

There are two window lift relays present in the wiring diagram .I just looked at for the wiring in the north American 123 models. plus there are two circuits as I described. I assume it is the six wire plug that became partially disconnected? Post the year of your 240d so I can go over the specific wiring diagram. They all probably are the same in this area but stupid to ignore that they may have made some changes over the years. I doubt you have done any serious damage by the way. I or someone else may be able to make a suggestion.