F53 Brake Controller

[Subdev10]

i need some wiring help. I have an '07 Hurricane on the F53 with a factory 4-pin plug. I needed to add a 7-blade and a brake controller for a new tow dolly. I found the gray harness very tightly wrapped under the dash to the left of the column. You virtually have to remove the dash so you can use two hands to locate the plug. When you do, the controller harness plugs right in easily. My problem is that underneath the coach, about 8 feet back of the firewall, there is a blue wire and a white wire that Ford has terminated with butt connectors. The blue wire should be the brake control wire. I'm assumed that the white wire would be the power, and that it should run back to connect to the black power lead at the back of my new 7 blade plug. So I wired the white wire to the power wire at the plug. When I tested the connection, the wired started to melt on the tow Dolly's battery break-away!! Any ideas? Was the Ford white wire really power?? Thanks.[

[JamieGeek]

My only suggesting is to try to trace the wire back to where it came from by crawling around under the coach.

According to this guy (page 14) the white wire is "electric brake ground":
https://www.fleet.ford.com/truckbbas...f5306mtrhm.pdf

[Subdev10]

Thanks. I've traced it back, but it just goes into a much larger harness loom above the driver's side leveling jack. The new 7-blade plug comes with a short ground wire with a round connector already on it. So if the under-chassis white wire is a ground wire, then does that mean it gets grounded anywhere on the chassis and does not connect all the way back to the plug? If it is a ground wire, does that mean that I have to run a brand new power wire from the plug all the way back to the battery?

[JamieGeek]

I would presume as much that if it is ground it is tied to the chassis somewhere. The document I linked to does list other wire functions and their corresponding color codes.