Case closed: it was the foam, my GB got the light back! Thank you very much for your concern, and of course, very special thanks to EGR!!!!!
These forums rock!!!!!!

Samwave, there's nothing at the PCB that indicates that there should be any contact for that brown ribbon.
kitsch, as you say, it's just an outright dead panel, so it looks like a contact issue. I didn't force neither the membrane nor the circuit board, I just used a specific cleaning product for electronic boards and I waited till everything was completelly dry. I do hear the whine you say when I turn the switch to light mode, so that seems to work. As I said, hope it's the foam! I'll let you know.

Thanks to all of you guys, I really appreciate your help!!!!!

No, I don't have any foam pad under the EL contacts, and I didn't notice that any piece slipped away when I opened it. But now that you pointed that, it's crystal clear that I misssed it!!! So I'll have to replace it. As soon as I get one and try it, I'lllet you know if it worked. Thank you so much!!!!

Hi everyone!! I just found this site and I'd like to ask for help with my GB light:

I recently opened the GB in order to clean buttons & rubbers, since some of them were working really bad. It went well, now all of them work great, but the light doesn't work!! Now, there's no difference between "on" and "light" mode.

  I assume that, in my ignorance, I didn't realize how to connect the EL light back when I opened the GB; Can anyone please tell me how to do it?

Or maybe did I break something and there's no way back? I'm posting a couple of pictures:

Thank you very much!!!!