Installation of a Brake Controller and 7-Way on a 1997 Ford F-150

Question:

On the back of the truck it looks like there was a bracket for a 7-way but now a 4-way plug is there. Above the spare tire on the frame is a plug with a extra orange and blue wire not connected. Under the dash, next to the diagnostic port, just wires are hanging down but no plug. The wires are light green, blue,red,white and Brown. You can see the screw holes in the lower dash for a brake controller at one time. A fuse is in the fuse box for tow vehicle. My question is since all the controllers come with plug in wires and the plug is missing under the dash will I just have to cut the plug off and direct wire? Can a plug be bought for the missing one? Looks like all the controllers come with 4-wires and under the dash there is five? Appreciate any help and wll order through you if you can get me on the right track. Thanks,

asked by: Vic P

Expert Reply:

First, many brake controllers actually come with a universal harness with one end that plugs into the back of the controller and on the other end are just blunt cut wires, no plug. Some vehicles that can have a plug will have an optional harness, sold separately, that has a plug on each end.

Your 1997 Ford F-150 could have had a factory brake controller connector to plug in a controller but it sounds like it was removed. If anyone has that part it would be a Ford dealer. But it isn't something you have to have.

It is also possible that if you follow the wires they could actually be attached to a plug and, if so, then you could potentially use the vehicle specific harness for the brake controller.

The wire colors you mentioned under the dash are the Ford factory brake controller harness colors. Red should be 12 volt power and would go to the brake controller black wire. White is ground and will go to the controller white wire. Light green is input from the brake switch and will go to the brake controller red wire. And the blue on the truck will go to the blue on the controller. The brown wire is for illumination and will not be used.

Regarding adding a 7-Way at the rear of the vehicle you will need # 37185. The 4-Way you have will plug into this adapter. Then you will ground the white wire to the truck frame. Follow the 4-Way wiring forward on the truck until it meets another connector. This other connector has more wires going into it than coming out. It sounds like you have found the orange and blue wires. Orange will go to the 37185 black wire and blue will go to blue.

The last wire is for reverse lights and you would just tap into a reverse light wire behind a tail light if it is even needed. If not needed you can tape it up and stow that last wire out of the way. I have included a link to an article that should also help.

expert reply by: Michael H