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Discussion Starter #1
Is anyone aware of any official instructions or directions of any kind from Subaru regarding how to install a trailer brake controller? My local Subaru dealership tells me that these cars are not supposed to use trailer brakes and that they can tow 2,700lbs without it, the manual says trailer brakes are REQUIRED over 1,000 lbs and that ELECTRIC trailer brakes are recommended.

While attempting to install my brake controller wiring, a $500 wire harness melted, requiring a $107 tow to the dealer and approximately $1,400 in labor/diagnostic fees to replace the broken components at my dealership. It appears Subaru doesn't provide a connector to plug right into like other manufacturers. As of right now, I'm under the impression that Subaru sells tow rated car, requires you to have brakes if you tow over 1,000 lbs, but expects the customer to figure out the electrical wiring on their own.

Back to the main question:
Is anyone aware of any official instructions or directions of any kind from Subaru regarding how to install a trailer brake controller?


Thanks in advance!

(if this is a double post, I apologize, I did not see it within 10 minutes of posting the first time)
 

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On the Super Mod Squad
2002 3.0 VDC Wag + 2018 2.5 Leg Ltd
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based on your other posts you have a

2018 Outback 3.6r

helpful for posters typing of what is available for your car, vs. say a 1994 2.2 wagon.

you can type that out once and for all by filling out the about my car section here. and it will appear under your name at the left of each post:

http://www.subaruoutback.org/forums/profile.php?do=editprofile
 

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2017 Outback 3.6R Limited with Eyesight. Currently totally stock
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I wouldn’t bother with wired these days. Wireless controllers are the thing now.
In my job (Software developer) for critical systems, I kinda developed the attitude "The more I know wireless, the more I like wires".
I have no idea but I'm willing to learn about the idea of using a wireless connection between a Vehicle and a trailer. It is useful.
 
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Yea life suport wired for sure. Trailer brakes? Meh no big deal.

Chinese routers? They all have back door factory built GOV access for the Chinese. LOL
 

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I wouldn’t bother with wired these days. Wireless controllers are the thing now.

https://www.etrailer.com/Brake-Cont...MImc-Dq_DE2QIVj4F-Ch385QiKEAAYASAAEgLNdfD_BwE
From what I read, you still need to provide 12v power from the vehicle through a 7-pin adapter (plus light signals that are already provided on the OB wiring harness) so at least that much wiring is involved. But the brake output level is wireless.

I didn't look to see if there are battery operated wireless controllers that wouldn't require 12V and could then use the 4-flat from the OB.
 

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2018 Dark Blue Pearl Outback 3.6R Premier
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From what I read, you still need to provide 12v power from the vehicle through a 7-pin adapter (plus light signals that are already provided on the OB wiring harness) so at least that much wiring is involved. But the brake output level is wireless.

I didn't look to see if there are battery operated wireless controllers that wouldn't require 12V and could then use the 4-flat from the OB.
The electric brakes themselves require power from the vehicle, I would think.
 

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The electric brakes themselves require power from the vehicle, I would think.
Sure, so it isn't really the "wireless" solution that some would think it is.

I almost added a 7-pin connector, and I still might, but there are a couple of things you have to keep in mind.

The OB is pre-wired for a 4-wire connector. That's going to be brake lights, signal lights, and parking lights, along with a ground wire.

To add a 7-pin for trailers that use brakes, you have to add a separate ground. If you look closely at the 4-7 adapters, you'll see the ground wire on the 7 side is a much heavier gauge because the brakes draw more current. The 7-pin adapter will plug into the 4-pin at the car end, but the ground wires do not connect. The existing ground on the 4-pin simply isn't used, and there will be a separate, long, heavier gauge ground wire that comes out of the 7-pin. You will need to tap a screw into the frame to ground that wire. At that point, you will have control of the trailer's lights, but not the brakes.

Wiring up the brake controller then requires a 12V fused line from the battery to the 7-pin adapter. Now you have power to the trailer.

But you still need the brake controller. That's going to be another wire from the controller through the 7-pin adapter for the brake actuation signal, and one additional wire if you wire up the reverse lights. If you go "wireless", you can skip this step, but you still need to do the rest.

I don't know what went wrong with the OP's installation.
 

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Discussion Starter #9
But you still need the brake controller. That's going to be another wire from the controller through the 7-pin adapter for the brake actuation signal, and one additional wire if you wire up the reverse lights. If you go "wireless", you can skip this step, but you still need to do the rest.

I don't know what went wrong with the OP's installation.
That's what went wrong. I managed to tap into the wrong wire in the brake pedal's harness. So far it appears Subaru gives no instruction on which wire it is, or how to do it. They just tell you you're required to have trailer brakes over 1,000lbs, and they recommend electric brakes (which require a brake controller).

The red wire from my brake controller was tapped into the wrong wire of that brake pedal's harness. $2,000 dollars later, my car should be ready today. Then, I guess I give it another shot, and if I get the next wire wrong, I have to keep paying Subaru $2,000 to get it fixed? I would really like to know Subaru's official guidance on using electric trailer brakes.

Imagine you're a television manufacturer. You advertise "You can watch DVD's and Blu Rays with this TV (but we require you buy a DVD player)!!!" Then, when someone buys a DVD player as you required, you don't actually have an HDMI port to plug into, and you don't offer a service to hook up the DVD player. The consumer is expected to take off the plastic covering of the TV and start splicing wires.
That's insane.

Now imagine you're a car manufacturer. You advertise, "You can tow 2,700lbs with this car (but we require you have trailer brakes)!!!" Then, when someone buys a trailer with brakes as you required, you don't actually have a brake controller interface to plug into, and you don't offer a service to hook up the brake controller. The consumer is expected to take parts of the dash apart and start splicing wires.
That's insane.

The other car manufacturers offer plug in play connectors under the dash. Why isn't Subaru?
 

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That's what went wrong. I managed to tap into the wrong wire in the brake pedal's harness. So far it appears Subaru gives no instruction on which wire it is, or how to do it. They just tell you you're required to have trailer brakes over 1,000lbs, and they recommend electric brakes (which require a brake controller).

The red wire from my brake controller was tapped into the wrong wire of that brake pedal's harness. $2,000 dollars later, my car should be ready today. Then, I guess I give it another shot, and if I get the next wire wrong, I have to keep paying Subaru $2,000 to get it fixed? I would really like to know Subaru's official guidance on using electric trailer brakes.

Imagine you're a television manufacturer. You advertise "You can watch DVD's and Blu Rays with this TV (but we require you buy a DVD player)!!!" Then, when someone buys a DVD player as you required, you don't actually have an HDMI port to plug into, and you don't offer a service to hook up the DVD player. The consumer is expected to take off the plastic covering of the TV and start splicing wires.
That's insane.

Now imagine you're a car manufacturer. You advertise, "You can tow 2,700lbs with this car (but we require you have trailer brakes)!!!" Then, when someone buys a trailer with brakes as you required, you don't actually have a brake controller interface to plug into, and you don't offer a service to hook up the brake controller. The consumer is expected to take parts of the dash apart and start splicing wires.
That's insane.

The other car manufacturers offer plug in play connectors under the dash. Why isn't Subaru?
Not sure how the brake wiring is layed out on the OB.

This is supposed to be the wiring diagram from a Tekonsha controller, it's probably similar to most others.

The controller needs to know when the brakes are pressed, so it taps into the brake light signal.



The diagram does show a 20 or 30 amp breaker between the controller and the vehicle battery.

When the controller senses the brakes have been pressed, it can sense the level of deceleration and send out a proportional signal out to the brakes through the 7-pin connector.

Subaru doesn't offer an OEM controller so they have to expect an aftermarket solution when they say that brakes are required > 1000 lb towing weight. (Unless you use surge brakes.)

As to why they don't have an under dash connector for a controller? The answer is more than likely $. They can put that connector on all their vehicles, and charge for it, and probably <1% of their customers will use it.
 

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Discussion Starter #11
I did all of that wiring just fine. It was the "Stoplight Red" wire that I tapped into the wrong wire with. That melted the wiring harness coming out of the stoplight switch.

I understand it'd be more money...it'd probably cost less than a dollar per vehicle for them to add that across all their vehicles. It'd just be a plastic connector that is already wired to the proper wires. If they're not going to offer it, why aren't there any sort of instructions or wiring diagrams they offer their consumers? (I understand you don't know, these are really gripes and questions for Subaru as a corporation)
 

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I did all of that wiring just fine. It was the "Stoplight Red" wire that I tapped into the wrong wire with. That melted the wiring harness coming out of the stoplight switch.. . .
The red wire from the controller should neither apply any significant voltage/current to where it's connected nor draw significant current from the circuit it's tapped into. The fact that something caused a lot of current to flow after it was connected, sufficient to melt the wiring harness, suggests the possibility that the tap might have involved more than one wire in the harness; i.e., the tapping device shorted between two harness wires, while at the same time connecting to the red wire from the controller.

Otherwise, the overheated harness would suggest there's a problem in the controller. Perhaps it might be an idea to make sure the controller itself isn't faulty and either applying significant voltage to the red wire or grounding whatever it's connected to.
 

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Brucey
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There are trailers with brakes that use a 4 pin connector. They use surge brakes. They're OK.

I've towed 2000+ lbs with mine before. Little U Haul trailer. I appreciated having the surge brakes.

I imagine Subaru was thinking about a similar set up when recommending trailer brakes above 1000 pounds.
 

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Discussion Starter #14
There are trailers with brakes that use a 4 pin connector. They use surge brakes. They're OK.

I've towed 2000+ lbs with mine before. Little U Haul trailer. I appreciated having the surge brakes.

I imagine Subaru was thinking about a similar set up when recommending trailer brakes above 1000 pounds.
The Owner's Manual actually recommends the electric brakes. ...so there goes that. :(
 

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Discussion Starter #16
That video is extremely helpful. I used it for most of my install. My troubles ran into trying to test the wires under the dash. The video doesn't really show you where a good grounding point is down there for the wire tester. I couldn't tell if I had a good one or not, and the tester that comes with that kit was a pain, it's one of those probe testers. Getting frustrated, I checked another outback with a brake controller hooked up and it was hooked up to the brown-white wire, just like the guy in the video has. I couldn't find a brown-white wire on my 2018 3.6r, but I did see a black-white wire and from the angel I was looking, I thought it was in the same pin. I WAS WRONG.

I wish I had bought a nicer wire tester and ensured I found a solid grounding point first, but I really didn't think this was going to cause any damage if I was on the wrong wire. I figured it just wouldn't work and I'd have to keep trying. Like it was said before, that red wire shouldn't have been pushing any power into the wire it tapped into, so I didn't really see what bad could have come from it. Also...I'm not an electrician!!! So, I didn't really think about what could go wrong here. Which adds to why I'm a bit frustrated that there's no official route to get this done. In this case, I'm just a dumb consumer who bought a car and I'm installing the brake controller for my electric trailer brakes the manual says I'm required to use over 1,000lbs.
 

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There are trailers with brakes that use a 4 pin connector. They use surge brakes. They're OK.

I've towed 2000+ lbs with mine before. Little U Haul trailer. I appreciated having the surge brakes.

I imagine Subaru was thinking about a similar set up when recommending trailer brakes above 1000 pounds.
I've pulled a tow dolly with surge brakes that seemed to work pretty good as long as you didn't need to back up very often. They may not all be the same but you couldn't back up until you disabled the surge brake by putting in a pin. Other than that it would be a decent alternative to installing a brake controller, especially if towing isn't a regular thing.
 

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U Haul told me they could install the wiring for 7 pin controller for our electric brakes but I saw a YouTube clip that noted complications. Suggested a memory device of some kind to protect other electronics like navigation. Any comments? SOA warns about after market devices but OB only comes with the 4 pin.
 

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Thinking about the memory warning I believe the point is addressed in the owner manual which states that certain presets on the radio and probably navigation routes can get lost when the battery is disconnected. Not a biggie and not actually caused by the brake controller operation just the install procedure.
 
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