Ok so I have a 2008 F150 SuperCrew XL 4.6L we're going to be towing a small PUP trailer (12' with elec brakes) Already have a brake controller, wire pigtail to plug it in under dash, have a generic 4/7 pin converter. Truck doesnt have the towing pack but does have the 4pin under the bumper.

my question is... if I go get the wiring harness from ford for the 7 pin from under the driver door back to the bumper, does it replace the entire rear wiring harness or just the trailer lines?

if I dont get it, how do I wire the ebrake? (blue wire) from the connection under the driver side door or from the controller itself??

not that i dont want to get the harness, but I bought everything before I was able to find the harness I needed. I can get it easy, but then i gotta try to return the other wires...

thanks

Josh

 

Umm....

I haven't seen a F150 newer than 1997 that didn't have the blue brake wire ran all the way to the back of the truck. If you follow the 4 pin at the back to where it plugs into the truck wiring harness between the spare tire and the rear bumper, you will see the wiring harness that contains the blue brake wire. It will also have a brown wire with a green trace (reverse lights) and an orange wire (aux charge line). These are the other 3 wires that make up 7 pin total. These are the connections needed to plug in a factory 7 pin trailer connector. To install a brake controller there is a grey wire connector behind your OBDII diagnostic port above the gas pedal on the bottom of the dash. You will need to purchase a wire harness that plugs in there and it will wire into your brake controller.(don't match color for color--they aren't always the same--read the dirrections)

In 1997 Ford standardized their wiring harness for all possible installation options. By doing so you just need to install the upgrade and install the corresponding wiring harness to plug into the main wiring harness.

 

kool thanks alot for the help. didnt really want to take everything back lol

yeah i already got the pigtail that connects to my controller and plugs into the factory harness under the dash. was just getting iffy bout the missing 7pin wires. but I'll get under it tomorrow (if i get time) and find the other wires.

thanks again
Josh

 

I just did this on my 05. I bought the harness for $30 and got a 7 and 4 pin combo from Uhaul. If you go that route let me know I have part # for the harness. Just follow back the factory 4 pin you will find the three wires that you need. I think they are all next to each other.

 

I replaced mine, the 4 pin with a Ford 7/4 pin combo, easy as Madonna to install. Just unplug the old one at the taillight, along the frame and unscrew the ground. Installing is basically the reverse as long as the thing actually bolts up, which it should. Underdash was plug and go and I needed 2 relays underhood. That's it.

 

my truck is only missing the #5 relay, but I've heard a few guys say "under hood"??? all I see is the kickpanel box and nothing under hood!?

 

'97 through '03 trailer fuses and relays were located between the brake master and the fender.
'04 and newer got relocated into the cab.

 

I think its on the passeneger side under the dash on the outside wall of the interior.

 

ok so i have everything hooked up except.... I can't find the brown wire with green trace.. there is a brown wire with white line and a solid brown wire. there is also a thrid wire on the outside thats next to the blue wire. its a white with blue line???

 

Brown w/ a white trace is running/marker/park lights.

Brown w/ a green trace is reverse lights.

White w/ a blue trace?? Not trailer related.

If you can't find the reverse lights to wire up don't fret. Most trailers don't have reverse lights anyway. The only reason you might need them is if you have a boat that has hydraulic surge brakes with an electronic reverse lock out.

Reverse lights are also not a DOT requirement on trailers.

If you must.... locate the wires coming from the drivers side tail light and follow them back to the main wiring harness. There should be a reverse wire located in that bundle as well.

 

ok thanks.. I dont think it has reverse lights. its the only thing not hooked up.

Thanks again