This Ford TSB Q-206
(Technical Service Bulletin) shows where to find the connector on the F-53 chassis. There is one location for model years 1999-2011, and another location for model years 2012 and later.
A Ford-provided connector under the dash has six pin positions and up to five wires in it:
Pin 1: Blue wire - brake controller output to hitch connector
Pin 2: Green wire - brake signal input to brake controller
Pin 3: Red wire - constant (not ignition-switched) 12V+, fused at 30A
Pin 4: White wire - ground
Pin 5: (optional) Brown wire - parking lamp (illumination)
Pin 6: Empty
Ford provides a pigtail to coach manufacturers that plugs into that connector. This means that you may see labeled wires under the dash (the ends of the pigtail wires), rather than the connector. Gently pull the labeled wires down from under the dash to bring the connector out into the open.
Once you have the connector and pigtail out where you can get to them, you have two choices for wiring up a brake controller quickly:
1) Wire the controller to the ends of the pigtail wires, or
2) Remove the pigtail and attach a pre-made adapter
This is a link
to the correct adapter to connect a Tekonsha brake controller to the Ford connector.
There is no need to cut off the Ford connector, if you use the pigtail or the adapter above. With the adapter, it is truly plug-and-play.
If you have not already chosen a brake controller, the Tekonsha P3
is a popular choice.