e36 18 button OBC (from 11 button) helpful notes
In the process of doing my 18 button OBC converson i've come across a couple of things in the DIY's that I felt I could help clarify and maybe add to it. Just giving some back to the forums that helped me get mine done, please spread this to other bimmer related forums where you are registered but please do credit me for the notes as some may require further clarification.
x1070-Pin 8 to x10182-Pin 12 wire should already be there in cars with previously existing 11 button OBC. You can perform a continuity test with a multimeter to verify The CBE(Central Body Electronics) Module is behind the glovebox and it has three connectors that are visible upon glovebox removal. Unfortunately the connector you are looking for (x10182) is of a smaller size and is located on the opposite side of the module. Remove the 3 connectors on the front (all different colors, one being black, forgot the other two colors) and then press down on the two tabs holding the module in its mounting bracket. It should now slide out. Now you can visually check to see the wire in pin 12 and make sure its the same color wire that you see coming out of pin 8 of connector x1070. Any further testing (continuity, to make sure its the same wire) can be done with a multi-meter.
Some of the DIY's call for x1071 - Pin 7 and x1071 - Pin 5 to be connected to a while/yellow and white/violet wires(respectively), "somewhere around the driver's side foot area. It is ridiculous to try and find these two little wires "around the driver's side foot area". I have come to the conclusion that these wires are also terminating conveniently in the x16 and/or x17 (don't remeber which one or if its both) connectors that plug into the instrument panel, and you can easily tap into the wires from here.
If you have also added the BC turnstalk, some DIY's call for a wire from x1071- Pin 4 to be connected to the brown(ground) wire on the harness of the turnstalk. This caused the 5-sec delay and PROG 1 message to appear and be stuck on the screen of the OBC. This is because it is constantly grounded and that should only be the case when you are programming the desired order of functions that you want to see when pressing the turnstalk repeatedly. For the turnstalk to work properly I have connected x1071-pin 4 to the yellow/red wire on the turnstalk's harness.