Keystone does not provide electrical, plumbing or chassis/structural blueprints or schematics for any of their products. Dealers also have the same problems that owners have and can not get that information from the factory. All I could suggest is that you look at the wiring "in front of the damaged area" and "behind the damaged area" and use wiring to "connect the similar colors" after which you may need to do some troubleshooting to confirm the connections.
Frustrating, absolutely, but owners have been asking for schematics and diagrams since I've been on this forum and none have ever been successful in getting their hands on the information.
Good Luck !!!!!
ADDED: It sounds like you've got your running lights and brake lights tied together "somewhere"... There's no other reason for the brakes to be activated when "the two green wires are connected"... Somewhere, (probably ahead of the damage) you're activating the brakes. If I remember correctly (and I may very well be wrong) there are three wires to the rear lights, brown, yellow and green. One is for tail/running lights, one for left brake/turn signal and one for right brake/turn signal. All 4 brake assemblies are "tied together", so you may need sit and stare at it for a while and think through the connections.
again, good luck
2015 F250 6.7l 4x4
2014 Cougar X Lite 27RKS