E46 Radio illumination

Hey guys

I have ran into a problem after installing my new radio.. I have no light in my buttons on the new radio, its a android radio. I now have to find the illumination wire from the original harness and connect with the one for the radio.. But here is my problem, i can’t find any wiring diagrams of the plug.. I can’t use a voltmeter as of right now, so if any of you guys could help me find the correct wire it would be awesome! Wire color or number doesn’t matter.
OEM is the small screen business navigation, with radio in the booth and cd changer in the back also. I have a blue connector in the front where the original “screen” where plugged into. I can’t find a diagram of this plug, because i simply dont know what it is called. Hopefully someone can help me.

Btw i have hardwired the harness from the back to the front of the car to be able to install the new radio.

Best regards