no constant power to head unit

[Manual Calais]

Hey, I am putting a new head unit into my 89 vn and for some reason there is no constant power(orange) to the head unit anymore. It had it from my old head unit and it was working breifly then stopped. I was wondering what could have happened while i was doing it to stop it working or is there somewhere i can tap into thats close by? and yes there is power at the fuses both sides and the fuses are not blown.

thanks

 

[Aussie V8]

and yes there is power at the fuses both sides and the fuses are not blown.

Trace the wire from its source, after the fuse box, and see where the break is or just run a fresh one from the same spot.