Hi Brian,
Thank you for your answer.

Well, I saw it was for E60 and E63, but realoem calls it as part of the SA638 kit ...the VERY SAME kit which is installed on my car, so I thought I may use it.
You know, sometimes OEMs' use the same parts on different cars just with a different part code.

About electrical contacts, they look clean and shiny and I did already clean the ones on the sim using a pencil eraser.
...and again, looks strange we have dirty contacts on 2 different slots (one is in the center armrest and the other is on TCU).

Other strange thing is that looks like the phone gets aware of sim insertion ...it changes from "please insert sim" to "please wait" on display, then back to "please insert sim" after a few seconds.
Same with a couple different sims which, btw, work like a sharm on my cellular phone.

Are you really sure I cannot use the TCU I found on ebay despite the different car model it was designated for?

And what about buying just a TCU and make it work with the handset I already own..? ...do they pair successfully or need some dealer work on it..?

Thank for your help.