Brake Controller HELP!

[GPFunFinder]

We have spent more hours that necessary trying to get our brake controller to work. We actually have tried 2 different ones.
The first one displays a "short" signal.
We checked all wires and we can't find any chaffing etc.
We installed a simpler controller and it works in reverse but not forward.
Any ideas?

 

[GPFunFinder]

We found the culprit. Followed the blue wire back and whomever originally installed it let it rest against the catalytic converter and that fried the wires. Spliced and re-routed and it works!