I just bought the pioneer MVH-1400NEX head unt for my ml320 and along with it i purchased the Scosche MZ07SR wiring interface. The wiring interface came preconnected to the wiring harness that plugs into the new headunit so all that was already done. Now i am lost as to what to do next. I already went ahead and ordered the adapters for the backup camera and bluetooth microphone so that is put of the way. My next step should be to set up steering wheel controls. I know the key1 and key2 wires on the new head unit are for steering wheel control but i do not know where to actually attatch them to the vehicle. would that be on the other 18 pin connector that was attached to the old head unit? Also i do not have any sound, which i have found out is because the 8 pins that come out of the new wiring interface dont actually connect to anything. how to i go about connecting those 8 pins to the speakers and subs in my car? would that also be on the other 18 pin connector? or is there an external amp that i neet to run those 8 pins to?