Hello Out there! Got my new WMS BB2 Videoslot yesterday and got a nice Topper too.....just LED s inside

left side one
there is only one plug that comes out of it three wires a black yellow and blue wire.....
but i dont know where i must connect this plug with the machine?
can anyone of you help me?

plug on the left the right one i connected with the top with a screw
i am very sure that the plug goes into a platine behind the lower PC Screen , there are some free plugs but dont know where to put this plug and its wires in!?

behind the top Screen there is nothing that looks like to connect with.....

thank you for your help
It is much appreciated!