I wanted to say thanks to everyone that posted info on adding the 7 pin trailer towing harness to my 2000 F150 that did not come with the trailer towing package. Here are the part numbers I used to get the harness and the pigtail for the brake controller:

" YL3Z*13A576*GB " 7pin / 4pin connector and harness
Cost at Ford Dealer $47.25

" F85Z*14A348*AA " Brake controller pig tail
Cost at Ford dealer $5.10

Pigtail and two relay kit that comes with F150 that has the trailer towing package Part # is: " YL34*15A416*AA "

I lowered the spare tire and pushed it aside and replaced the harness in about an hour. Perfect fit, plugged right in. Bolt the connector to the hitch receiver and thats it. The pigtail for the brake controller plugs in under the dash, just to the left of the center hump. I mounted the brake controller on the fuse panel cover part of the dash. I checked and all the fuses and relays were already installed that I needed. As best I can tell the two relays that come with the tow kit are for the backup lights and the battery charge circuit from the truck to the trailer. I don't use either, so I will be fine without the relays. I hooked up to my travel trailer and all worked perfectly the first time, including the brake controller. From what I can tell all late model F150's come wired for the brake controller under the dash and all that is needed to add the 7 pin connector is to change the wiring harness in the rear. By the way the new harness also has the 4 pin connector on it, so you don't need an adapter any more as you did on some of the earlier models. I do have one question about the wiring harness. There is an extra wire coming out of the harness not going to the connector that wasn't used. The 4 pin harness has it also. Does anyone know what that wire is for?

Thanks again to all for the great information, I'm ready to travel now!

 

That wire is an illumination wire. It's hot when your lights are on. It isn't on the dimmer however.

I'm pretty sure that the relays are for battery + and brakes. You should double check.

 

Hi larry

Always a good feeling when you install, and all works ok.

A word of caution...this may/may not apply to your TT?

If there is a "brake away switch" mounted on TT tongue, that has a hook up cable that goes to truck frame...That switch is activated by the TT battery. At least thats the way it is on my TT.

Just curious...is this other type trailer that does not have a 12V batt? If it does have batt. you would need the chg. relay.

Thanks for update...

Good luck...OT

 

V10man,

Thanks for the info on the wire. I verified everything in the owners manual fuse list, both under the hood and dash for anything that said Trailer Towing and all the fuses are already in my truck and only missing two relays. At least on my truck it is the battery charge and the backup lights relays that are missing. My brakes, signals, and lights are all working without adding a relay. I have not seen the information that comes with the package from Ford with the relays and brake control pigtail, but maybe someone that has it can write in and confirm which relays are included in it. Thanks!

Old Timer,

You are right on, the brake away switch is operated by the battery on the TT. I always keep the TT battery well charged and ready to go when traveling, so it will work the brake away switch if needed. Good point! Thanks!

 

I just installed a new 7 pin harness on my 98 F-150 XLT, and it was a breeze. My problem is that the only signal I'm getting at the receptacle is at the battery recharger pin. The rest of 'em are dead. The ground is good, and so is the continuity on all the pins. So, I'm assuming my problem is a blown fuse or relay. I checked the #18 5 amp fuse, and it's fine. I haven't had a chance to look yet, but I'm guessing the #1 20 amp fuse in the power distribution box is blown, and I'll check the #28 30 amp brake controller fuse too. Is there another fuse that controls the turn signal and brake light connection? I'd appreciate any insight anyone has. I'm pulling a travel trailer, so I need everything to work. Thanks.

 

I just picked up the trailer wire harness with the two plugs on it. I was wondering what the two wires not in the harness ends were. I read the above post but from looking at my harness I'd guess that the large white wire is a chassis ground but I have no real idea about the little wire on the 4 pin side. this wire is green on my harness. I guess it could be a brake controller line for trailers that require a 5 pin spade connector.

 

That extra wire is the illumination wire. It has 12V+ on it when your lights are on. Can be used for license plate lights or anything else you need to have on with your lights. Most people don't use it since the license plate is mounted under one of the tail lights and that shines down and lights it up.

 

I just installed the new 7-pin/ 4-pin harness on my truck. the
extra wire coming out of the harness is for third brake lights on camper shells.

 

hab,
check the small fuse box closest to the cab, under the hood next to the power dist. box, it's around 6"x2" that one should have two or three fuses. one of them controls brake/turn lights to a trailer.....let me know, this was the problem with my 98
dale

 

OK, what gives with the relays? I attempted to pull my boat this morning for the first time with my new 150 and discovered that the back-up lights didn't work. I traced it down to no voltage in the "standard" 7-pin, and then to the relay box which is missing the relays for back-up lights and trailer battery charging. Without that back-up light circuit, hydraulic surge brakes won't let the trailer back up.
Does Ford not supply these relays with the factory tow-kit. I'll be asking the service shop soon.

 

The relays are generally in the glovebox of the the trucks with the tow package. Most often they are in a plastic bag with a note. Some dealersships install them when they recieve the truck that way customers won't get confused about the spare parts and nonworking trailer plugs. I have seen a few trucks without the relays in the glove box, always figured some one needed them so they "test" drove a new truck with the tow package and pocketed the goodies. On the other hand I have seen a few dealerships that would remove them so the previous situation doesnt happen, and a few dealerships that remove them to sell to a new truck owner because " the tow package doesnt come with all the required parts". You know, $30 of parts and an hour labor to make your new truck work b.s.

 

Check my post on relays for the 4 pin to 7 pin conversion. The relay is under the hood in the power distribution box. Check your owners manual for the number and location. Your Ford dealer, and NAPA for that matter, usually have the part in stock.

 

if you have the towing package you should already have those relays!!! i just paid $8.00 for a battery charge relay.

 

What a HOOT!!!! After securing an "appointment" (07:00) at the service bay, I met a new service advisor, who was on his first day in the check-in lane, and I was his first customer; lucky me. When I realized the depth of his youthful fog, I took him to the rear of the truck and pointed to the 7-pin plug and told him that it was for a trailer hook-up. I then told him that the relays that make it work are missing, and there is a kit that also includes a pigtail, which I need to be given. After his "supervisor" showed him how to log onto their computers, he had me sign a paper directing them to "install pigtail." 20 minutes later he brought two "technicians" to me, and I explained the existance of the kit, and what it was for. 10 minutes later, I saw the technicians wandering through the lot of new trucks in the front of the dealership. They found a truck with a towing package, and then came in to get the keys. One told me they needed to take the kit from a truck to show the parts department what they were looking for. I told him that if they could get their hands on a kit, just give it to me and I'll install it. 10 minutes later the technician brought my truck to the front, signaled me to come to it, and told me the kit was laying in the seat. So, after educating 3 "service advisors" and 2 technicians, I have the relay/pigtail kit that should have been delivered up front. Apparently, I'm the most qualified guy to install it. It's part number is "2L3T 15A16 BA". This looks to be a version that will also work with the Harley package, and most of the instructions are in Spanish.
Marvelous! Is this what the Ford service will be like?

 

my truck didn't come with a towing package so i'm adding the 7 pin and the relays. when i went to the parts counter and asked about the relays, they looked at me like i was from Mars. i had to get the owners manual and show them what i was talking about.