7pin conversion from stock Ford towing package 4 pin trailer harness

[Ksnau]

Hello, so I'm getting a trailer soon and pretty much all trailers. Even small ones under 3,000 lb that don't require brakes, well they're putting them on pretty much all of them now anyways including the one I'm getting next week. So here's how I'm putting on a seven pin connector And a brake controller.

1. First thing I had to do was get the stock 4-pin out. Now I have the ford towing package. I don't know what you have to do to add a four pin if you don't have the towing package, but it should be pretty easy and I believe there is at least one post about it.

So to get the four pin out it's connected to an L bracket that comes off of the subframe and there's four plastic tabs that hold it on there. And as far as I could tell, there's no way to remove the four pin trailer harness connector without just cutting them off. So that's what I had to do. There's two flat tabs on each side and there's two on the top and the ones on the top are more of an L-shape.

First, you have to disconnect the 7 mm screws that hold the black plastic bumper cover on. You don't have to take it all the way off. Just take off the four screws on the driver side and that'll allow you to kind of peel it back to get under there where the four pin connector is and I was able to just use a normal Dremel tool with a small cut-off wheel they sell them at Lowe's and home Depot. They're like an inch and a half cutoff wheels And if it's the first time you're buying it, you have to buy the one with the adapter to hold the wheels. But that's how I got most of them off but the one closest to the middle on the side. I actually had to use a small hand saw to cut off but it's plastic so it's very easy.

2. Once I did this you can pull it out. It does take a little bit of work but you don't have to rip it out or anything. And now the problem is I bought a 7-pin harness adapter off Amazon which I'll put the one I got in the pictures but it was like $16 before tax and I had to trim the plastic corrugated wire shielding so that it was only about 3 in long. So otherwise It makes the adapter really long because that corrugated stuff can't bend very sharply.

3. So then I had to make another L bracket to mount the seven pin adapter on. So I just drilled two holes in the L bracket that the four pin was connected to by those tabs. I used a 5/16 drill bit. I think it's just an old drill bit that I have that cuts through metal really good but it's not labeled but it fits in my DeWalt drill bit case exactly where the 5/16 would have gone.

4. Then I just made my own L bracket. You probably could buy one but mine was basically an L shape that was 4 in long by about 3 in wide and then the other half of the L was about 1 in by 3 in wide, actually the easiest way to explain it is I basically did it the same size as the bracket that came with the Amazon seven pin adapter Now the holes on the stock Ford bracket that held a four pin. They're not in the same location as the Amazon bracket so just make sure and drill the holes on the right side of the L bracket for each of them cuz the short 1 in side goes to where the four pin connector was and then the long 4-in side of the L bracket is what the adapter bolts to.

And I just went to my local metal shop industrial metal supply in Phoenix. They're near 40th Street baseline and they're awesome. I've been going there for over a decade. I love them. So if you go to these metal shops usually they have a remnant section and if you just need like one or two pieces that are small and you can get them out of the remnant section sometimes they'll l give them to you for free. Or at least this place does. So I got a approximately 8-in long section of t6061 aluminum square tubing and cut my L bracket out of that cuz it already had the shape that I wanted so I didn't even have to bend anything and it's aluminum so it won't rust and I don't have to paint it or anything and it's a lot easier to drill through and work with except for welding.

So using the bracket that came with the Amazon 7-pin adapter, I traced two holes that would go to the seven pin adapter L bracket and then the other two holes that I'd already drilled into the Ford 4-pin L bracket that's on the bronco sport already and that's how I mounted the adapter I'm going to post later once I've got it wired how I did the wiring.

One note, I don't want mine on here permanent like I'm going to leave the aluminum L bracket on there that I made but I just don't like how much the seven pin sticks out. So I'm going to make the connectors so that I can plug them in and unplug them. So anytime I want to tow my trailer, I just screw the two bolts onto the aluminum bracket and plug in four wires. You could easily make this a permanent solution as well though.

I will post again when I have the wiring done and do my best to take some good pictures of how I did it.

Also, I've decided I'm going to get the Tekonsha prodigy IQ because I want a proportional controller. Seems like it's what everyone should get and not a timed one and that seems to be the cheapest one from a good brand name and the controls seem like they'll be comfortable for me.

 

[Ksnau]

For this topic sure it's hard to see where the wiretap is. It's a t-tap so I did a yellow highlighter Mark to try to show you cuz it's covered in black electrical tape to help make sure it stays closed. But that's where I tap the reverse light

So I didn't get as much done as I wanted to yesterday but I mounted the brake controller under the light switches. I wanted to do it in the bottom cubby but it was too close to my wireless charger which I was told could mess with it. So this was the next best spot where I could tell that it seemed like the screws wouldn't poke into anything and I could still reach it easily while driving. It's the tekonsha Primus IQ. It's basically the cheapest one that has proportion braking.

I also routed the reverse lights wire (yellow) That's what the other pictures are. Basically on the driver rear light when you unplug the light from the wire harness it's the top left wire is for the reverse lights and you can easily just follow the wires from the bottom bulb up to see which one's reverse.

I do still have to take it off again and get the brake light tapped cuz I'm going to use the brake light instead of the brake pedal for the controller to know when I'm hitting the brakes cuz I read that that's a little better and also it has less chance of messing with the ECU if there's any feedback although I will be putting a diode in between. I'm using the rm690 diode. It's the product in the picture.

And basically when I ran that reverse light wire I just dropped it down through the hole below the light. You can kind of see where it goes back behind the bumper and then it comes out on the driver side near the tailpipe and so I'll just route it under that plastic bumper and I'm going to put on a weatherproof connector for the 4 wires so I can just leave it hanging so I don't have to keep my seven pin harness adapter on there if I don't want to.

 

[Ksnau]

I did some more work but unfortunately it was so hot and so I didn't take many or very good pics.

Also, I just want to say these are not for sure instructions that'll work for everyone. This is just how I'm doing it. If you're not comfortable doing this yourself, you should either do more research. Get someone to help you that knows what they're doing or take it to a shop to have it done.

So last night I basically wanted to finish the seven pin harness that the trailer would hook up to. So the first thing I did since I have to run a brake controller is I started out using blue wire trying to match the colors on the brake controller harness and 7-pin harness adapter, but my blue wire ran out so I had to solder together some green wire. So at the front of the car it starts out blue. But at the back at the trailer harness it's green for the brake controller wire.

I ran wire just like I did on my air suspension from the brake controller which is right under the light switches along the plastics that are at the bottom of the door. Kind of tucking it under there and then when I get to the back seat you pull the seat halfway back/down and slide it under the vertical portion of the back seat in the space that opens up when you fold the backseat down part way.

And then I just drilled a hole 5/16" I believe, right next to the holes that I already had drilled for the air suspension airbag lines and used that to run the line to the seven pin harness. Now it was easier to do on the passenger side space wise due to my air suspension or I would have run it on the driver's side, also the power wire I was tapping into was on the passenger side. so I ran it on the passenger side over an existing wire harness to help keep it from hanging down and then I just did like I did with the yellow reverse light wire and I used the black plastic bumper to route the wire and keep it tucked up and not touching the hot heat shield for the muffles. I unscrewed the 7 mm screws that hold the black plastic rear bumper cover and tucked the wire behind those to keep it from hanging down. And then I also used a zip tie to tie the wires to where the emergency chains hook to but at the top to the chains don't rub against the wires.

And I basically just did that for each of the wires. I read that the power wire should be switched so I just tapped into the switched power I was already using for my air compressor because they're not using any power 99% of the time and it's on a 20 amp fuse I believe so I think it should be good to take the power and so I basically just stripped the plastic wire cover on that keyed power I had already busted an add a fuse to the passenger footwell to get 12 volt power to the harness and soldered them together. I think it was 12 gauge wire, and then I ran it down the same way that I did the blue wire.

For the ground, I just used one of the big bolts which I will try to put a picture up if I don't have one now and then again just ran it the same way that I did the others and I did test it before I finished everything to make sure that the ground would work with the power and it did. To do that all you have to do is get a multimeter put it on the DC area and I just do it to 20, which is 20 volts as I understand it so that's the max it will read so since we're on a 12 volt system that's sufficient to read what I need.

It'll go up to 20 volts like it'll usually say like 2 20, 200 under the DC section of the dial or at least that's how mine looks there are different types. and so I turn it to 20 and you just use the probes to touch the power wire and the nut that I want to use as a ground and you just make sure that it works and completes the circuit and reads around 12 vols. And that's one of the two things I know how to do on a multimeter of the like 800 things you can do with them. But don't take this. As for sure instructions. I am not an expert at all. If you don't know how to use a multimeter, get someone else to tell you how to use it first.

Once I had all the wires hanging down by the hitch, I went to AutoZone and bought a four-wire all-weather connector and soldered them together. That way I could just plug it together easy or unplug it. And I did the same thing on the other side to the seven pin harness adapter. So now I have a four-pin connector for those wires and have a four-pin connector for the stock tow package wire harness. So basically I have two wire connections that I plug in whenever I want to hook up a trailer. And then when I'm not using them they can just see stay there.

I'm going to figure out a better solution for stowing them But right now I just kind of have them taped on top of the aluminum L bracket that I made to hold the seven pin harness bracket. What I'll probably do is I can unscrew two of the 7 mm bolts on the black plastic bumper cover and just tuck them back in there when I'm not going to be towing because it only takes like 30 seconds to unscrew those so that you can move the black bumper cover enough to either put the harnesses in there or pull them out through the hole that already exists for the Ford towing package. That way I didn't have to do any cutting of anything. All I had to do was drill two holes in that steel bracket that held the four pin harness that Ford had on their stock.

And I'll put the pictures below. Also, the only tools I've had to use besides a normal ratchet and socket set are soldering kit that I bought from Lowe's like 20 years back for like 10 bucks. They're probably 20 or 30 now and a multimeter that I think I got from AutoZone when my last one broke back in like 2015 I think it was 15 bucks back then. I think they're 20 now and then just a box of some wires of 16 gauge and some 12 gauge wire cuz for the power and ground. You want to be thicker at 12 gauge minimum I believe. So be careful when you buy your harness adapter.

If you try to do this make sure that they put thick enough wires in there and I'll know that. From what I've read different companies do different things so gauges aren't always standard. Some companies will say it's 10 gauge and it'll look fat enough to be 10 gauge but all they do is put a thicker plastic coating around it and so it's really you know more like 12 gauge or something so just be careful of that.

 

[Ksnau]

So I did finish the brake controller and just got home this morning with the trailer.

For the brake controller I had to mount it right below the headlight switches. I wanted to mount it in the open area where the wireless charger would be if you had one, but the plastic was too hard with the screws they gave me and I was worried that I might poke into the temperature controls. But basically I just took their screws and to get the hole started in the leather material I used a tool that's like a point with a spring and you push on it and it like the harder you push. Eventually it'll like let go of the spring and it makes a little indent in the material to help you drill in the spot you want to, to get it started. I also used it's basically like a spike that you can Hammer on and I used that to basically get the hole started after I use the other tool to make it a little bigger and then I was able to just take the screws that because they were flatheaded not Phillips they didn't balance well so I had to use them with a 7mm socket but basically I just pushed on them and screwed them in and they went in pretty easily once I had the hole started.

For the brake controller power you need to use at least 12 gauge wire or that's what I was told with mine and that's what I used. I bought it from AutoZone cuz I didn't have time to ship it. It was like 10 bucks in there electricals aisle and basically there's a grommet that's like a rectangle. But on the shorter ends it's kind of curved and it's really good rubber where you can like poke a hole into it and run a wire through and it kind of seals around the wire and that's where I've run all my air suspension power all my gauge power and this power wires. It works really good and it's like right above the brake pedal under the dash on the driver side. Also in the power wire you have to run a 20 amp or at least for mine. You have to run a 20 amp auto reset breaker and I basically drilled a hole in the plastic below the windshield wipers to mount it cuz I didn't want it just bouncing around because it does have just little metal ends that you connect the wires to and I was worried that they might hit something and connect and short out or something. But basically you just run the power and ground from both posts of the battery to the controller and then you run the blue wire which is the brake wire in the seven pin trailer harness to the brake controller and I just routed it the same way I did my air Air suspension. I drilled a hole in the spare tire bottom pretty much right over the rear lower control arm and ran it from the 7-pin up into that under the back seat on the driver side in the corner there's like a hole you can use and then kind of shove it under thr plastic door molding I guess it would be called on the bottom part of the door openings. you can just tuck it under there and then run it all the way under that plastic to where the hood latch is and then you bring it up from there under the plastic under the steering wheel.

And to get the brake input wire or the stoplight wire. Some places say you can use a wire off the brake pedal but I used the stoplight wire on the rear driver side light because it said that if I did happen to use cruise control or something it might not recognize the brake pedal wire but it would recognize the brake light wire and for that I took a picture Also if you read my earlier posts the on the wire harness for the driver side tail light. If you have the hook part of the connector at the top, there's six pinholes the top left is the reverse light. The top middle is for the brake light. Make sure to use a multimeter to double check. It's not different on your car but that's what it was on mine.

Basically I ran the wire under the weatherproofing for the hatch and I took my grinder and just cut a tiny little quarter inch notch so the wire could go under the weather stripping without it poking out And luckily I had some leftover outside body paint for scratches that I used to kind of paint over so it would hopefully protect it from rust, and then I ran it under the plastic that is like the bottom of the rear hatch opening. There's two I believe 10 mm screws that you have to take out that are on the inside of the spare tire wheel well and then the plastic just pops up and I ran it under that. It'll show in the pictures

Then just like the brake signal wire from the trailer harness 7 pin. I ran it where all my air suspension wires went along the driver side bottom plastics and now you do need to put a diode in the brake light wire so it doesn't backfeed.

And another thing I found out you need to put a diode between the 12 volts power and the 7-pin trailer harness and your power wire. If you use the same power wire that I did on mine on the passenger footwell I guess because it was switched power. it was a switched fuse and I just used a little add-a fuse from AutoZone but it was back feeding from the batteries on the trailer and so I would turn off my car and the dash and everything would go out but the engine was still running so I had to unplug the trailer seven pin harness each time before my engine would turn off I have to put a diode in there which is like a one-way switch for electricity but pointing backwards so that energy can feed from the car to the trailer but not the other way. So it's basically the opposite way as the one on the stop light switch to the brake controller cuz you want electricity to feed from the stop light to the brake controller but not backwards if that makes sense

I'm really bad about these and I don't take enough pictures. I'm just really tired from my trip. Maybe I'll edit these later but if you just use the guidance online I used e-trailer mostly as well as the instructions that should come with your brake controller and harness. It basically tells you where to run the wires even though they don't have anything bronco specific And then basically you just have to find where to tap into those wires which these posts should tell you.

But even if not I mean you can take them $20 multimeter and just put it on the 20 DC setting and just test and read that it's coming out 12 volts or not it's the same on any car for the brake controller I just used universal stuff and found the. you have a power wire, a ground wire, a wire that goes to the brake wire for the 7 pin and a wire that goes to either the brake pedal signal or the brake light signal and then on the seven pin you either have to add a four pin or you already had it with the towing package and then you just have to add power and ground and you have to run a wire from there for the brake signal to the brake controller so you can control the brakes and then the reverse light and how I did that should all be above.

Also one more note, I did have to pull out the air intake box to move the battery forward and that lets you get your hands behind the battery to where the gromet is to make the holes and feed the wires a lot easier.