4 pin trailer harness to factory 7 pin
#1
4 pin trailer harness to factory 7 pin
If your truck has the factory 4 pin only harness and you have the wires in the harness it's a pretty simple addition to get the oem 7 pin.
You will need the following parts from Ford
FL3Z 13A576 B Harness
9U5Z 14489 MAA Plug
*Start by lowering the spare tire
*Remove the factory 4 pin harness (plugs in above the cross member and has a ground bolt on rear outside of driver side frame rail (10mm). Unplug the tag lights from harness.
*I used a dremel to cut out the plastic where the plug will pop in and then a file to smooth the edges.
*Push the 4/7 pin plug through the new hole in your bumper and it will click into place.
*plug the new harness in and install the ground bolt. You're good to go.
Took me about 30 minutes and everything functions like it should including my aftermarket brake controller.
You will need the following parts from Ford
FL3Z 13A576 B Harness
9U5Z 14489 MAA Plug
*Start by lowering the spare tire
*Remove the factory 4 pin harness (plugs in above the cross member and has a ground bolt on rear outside of driver side frame rail (10mm). Unplug the tag lights from harness.
*I used a dremel to cut out the plastic where the plug will pop in and then a file to smooth the edges.
*Push the 4/7 pin plug through the new hole in your bumper and it will click into place.
*plug the new harness in and install the ground bolt. You're good to go.
Took me about 30 minutes and everything functions like it should including my aftermarket brake controller.
The following 5 users liked this post by Moonshine140:
2002FX4 (09-01-2020),
Apples (06-19-2017),
ed1le (04-03-2016),
JT@2doorsdown (03-06-2016),
Mlarv (08-03-2015)
#2
Senior Member
iTrader: (1)
If your truck has the factory 4 pin only harness and you have the wires in the harness it's a pretty simple addition to get the oem 7 pin.
You will need the following parts from Ford
FL3Z 13A576 B Harness
9U5Z 14489 MAA Plug
*Start by lowering the spare tire
*Remove the factory 4 pin harness (plugs in above the cross member and has a ground bolt on rear outside of driver side frame rail (10mm). Unplug the tag lights from harness.
*I used a dremel to cut out the plastic where the plug will pop in and then a file to smooth the edges.
*Push the 4/7 pin plug through the new hole in your bumper and it will click into place.
*plug the new harness in and install the ground bolt. You're good to go.
Took me about 30 minutes and everything functions like it should including my aftermarket brake controller.
You will need the following parts from Ford
FL3Z 13A576 B Harness
9U5Z 14489 MAA Plug
*Start by lowering the spare tire
*Remove the factory 4 pin harness (plugs in above the cross member and has a ground bolt on rear outside of driver side frame rail (10mm). Unplug the tag lights from harness.
*I used a dremel to cut out the plastic where the plug will pop in and then a file to smooth the edges.
*Push the 4/7 pin plug through the new hole in your bumper and it will click into place.
*plug the new harness in and install the ground bolt. You're good to go.
Took me about 30 minutes and everything functions like it should including my aftermarket brake controller.
The following users liked this post:
Apples (06-19-2017)
The following users liked this post:
2002FX4 (09-01-2020)
#4
12v constant
Hello my truck currently has the 4 pin flat connector. I'm thinking of picking up the above mentioned parts as well as the factory trailer brake controler. Does anyone know if this harness/plug powers the 12v constant pin. I'm buying a camper and would like to charge the trailer battery while running down the road. Thanks
#6
Do i have to install a relay and fuse like the older models? My local dealership told me there was no way of installing the factor 7 pin and brake controler. I figured from the door it was just a body harness swap. Also how would i tell if i have the wires in the harness. I do have the harness for the brake controller located behind the tray.
Last edited by dissturbed; 09-27-2016 at 04:52 PM.
#7
Senior Member
iTrader: (1)
Do i have to install a relay and fuse like the older models? My local dealership told me there was no way of installing the factor 7 pin and brake controler. I figured from the door it was just a body harness swap. Also how would i tell if i have the wires in the harness. I do have the harness for the brake controller located behind the tray.
Next, find another dealer, that has a clue, to program your brake controller.
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#8
Thanks dude. I'm thinking of using forscan and enabling it myself.
#9
Ford Accessories Manager
Has anyone successfully done this 7 pin harness and the factory style in-dash brake controller? According to all my information from Ford, it can't be done as an after-the-fact accessory. I'm about to try it, but don't want to waste several hours if it's not going to work anyway.
#10
Senior Member
iTrader: (1)
Cool. Just ordered the MX Scan tool and downloaded Forscan so I can adjust the speedo for my new tires. Had I known about Forscan at the time, I'd of just ordered the scanner then vs. paying the dealer!
Several have done it, including myself, without an issue. It's a Ford OE harness. You simply remove the 4-pin harness and install the 7-pin. My truck was already pre-wired for the factory controller, as I believe all of them are. I just removed the pocket from the dash that had the factory harness connected to, connected the harness to the factory in-dash controller and then used the factory trailer plug on the bumper and plugged the 7-pin harness into that. Only thing you'll need to do is go to a dealer for them to unlock the towing options or purchase a scanner and download the Forscan program to do it yourself.
Has anyone successfully done this 7 pin harness and the factory style in-dash brake controller? According to all my information from Ford, it can't be done as an after-the-fact accessory. I'm about to try it, but don't want to waste several hours if it's not going to work anyway.