Audio Wiring (need help) :x

So im all about speed and a good system
Right now i keep trying to find a wiring diagram but none of them work
I think all my wires are messed and i want to wire up my deck
I tested all my wires trying to find the ground, ACC, 12V
i found the ground, and 12V
but theres only one other wire reading power when the key is turned and i think its the acc, its reading around 5 volts
should it be reading 5 volts or the full 12?
and how to i run the blue and white cable from the back of my deck


Right now i keep trying to find a wiring diagram but none of them work

I think all my wires are messed and i want to wire up my deck
I tested all my wires trying to find the ground, ACC, 12V
i found the ground, and 12V

but theres only one other wire reading power when the key is turned and i think its the acc, its reading around 5 volts
should it be reading 5 volts or the full 12?
and how to i run the blue and white cable from the back of my deck

