The unused plug on the bottom left goes into the steering wheel control box which then plugs into the ir plug on the back of the dvn.
It looks like you've spliced the fakra cable properly, it's worth noting that for first turn on (from memory) you have to press/hold the left knob to switch the unit on.
You'll also need to splice into a wire from the blue connector from the original head unit at the dash to get illumination. From memory it's the blue/red wire and it needs to splice into the orange Dynavin wire but I'd have to check my notes.
None of this should stop the unit from operating though...