I have a used broken Pioneer deh8400 and I think I repaired it. (power related issue).
Bottom line is that I want to check to see if this unit will power on without pulling out the dash and by wirekit and dashkit. I tried to connect power through my battery but it didn't work. (Hooked up yellow wire for power and black for ground)
How's my approach just to see if this headunit will turn on? Any more wires from the headunit I should connect?
Is the headunit just dead?

Thanks guys

 

Yellow is the constant on, you also need to connect the red wire for power.