These are the electrical circuit board's that I had to make some modifications to, to get a good ground to enable the flaps to work properly. The shifters will not work, unless the resistors are removed from the electrical circuit board .
I had to remove the two tiny 2mm resistors on each circuit board (or was it only 1pc. on one of the boards and 2 on the other? you can see the leftover from the solder) after that I cut of the two leads on the circuit board that has 5 wires, the white and the yellow/light brownish wire are removed. All we are using are the brown and red leads . The green wire will be connected to earth, inside the steering wheel. More about it hear; #6 SSG/SMG Steering Wheel Contacts
Usually a brown wire indicates earth but for some reason they chose to use green for earth (come to think of it, then I remember seeing green color used for earth in other places on e39). The only two connections left are brown and red and these are the ones we use for the up and down shift signals. Therefor you only need to solder or connect two new wires; one to the red and one to the brown wire. Then connect the wires to the two contacts that where meant for the steering wheel hating elements on the clock spring and now you are finished with the steering wheel setup itself and that goes without saying that you have mounted the clock spring to the steering wheel itself.
Note! The SMG circuit board is totally different from SSG.