Bypass breakaway to narrow down electric break issue?

[Fallon]

There will likely be a ground connection across the ball & hitch. However because it moves & is covered in grease it's likely to be flaky. Simple answer is do it right. Wire the plug ground to the frame.

 

[WM75Guy]

This tester has saved me a lot of time and effort tracking down electrical gremlins. It quickly tells me if the truck is the problem. I keep it in the truck glovebox along with my 6 pin and 4 pin adapters.

Ultra-Tow 7- and 4-Way Circuit Tester, Model# DBP7+4 | Wiring Kits| Northern Tool + Equipment

 

[petebert]

I rewired the brakes tonight and got all 4 to activate off a battery. Still no go from the truck. I tested the output at the 7 pin and only got .1 volts. So I then tested the blue wire out the back of the controller, got 11.5 volts. So it appears the controller is sending the voltage out and it's getting lost somewhere in my truck. The 12V battery pin wasn't getting voltage either. I checked the fuse box under the hood, the trailer brake fuse appears good, the 12V aux fuse wasn't there. Truck is a 97 F350 with a factory 7 pin harness. Can I just run a new wire from the cab to the back of the truck?

 

[Fallon]

New wire or finding the issue in the old wire are your only options... And like you determined with the trailer replacement is often cheaper & faster than repair when dealing with wiring.