well, i'm an idiot.
When i tested power source at the batter all good at the fuse before, at and after. Yellow wire with fuse holder built in.
so naturally I went to the back and tested the yellow wire. Has power so unit must be bad.
Order $80 new one, comes in quickly.
Installing this morning - still dark and wife sleeping and i'm bored so put on my trusty headlamp.
Get all swapped out and went to test on trailer and NOTHING.
Threw out the remaining half cup of coffee to grab one of my fake beers because working on cars boats and things require it even at 0400 on a Thursday.
Blah, blah blah - turns out the yellow at the battery is spliced to a black to continue to the unit at the rear of the vehicle. Go test the incoming black wire at the unit, nothing so apparently the forward splice is bad somewhere that i need to get under the car to see....
Could have happened when replacing clutch or during engine swap.
So now my boys have more crap to find and throw away when i'm dead.