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Discussion Starter · #1 ·
Does anybody know what kind of trailer wiring comes with the Subaru installed trailer hitch? Is it a flat 4 pin? I was told that I need a round 7 pin for a trailer I am buying? Can you convert a 4 pin to a round 7 pin? Any help is appreciated.

Brian
2008 Tribeca
 

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Just because you get a 4 pin to 7 pin adapter, it does not give you trailer brakes. It will only make your taillights/turn signals/brakelights work as they did with the 4 pin connector. Assuming otherwise is a very dangrous scenario, thinking that your trailer brakes work when they actually aren't even connected to anything on the vehicle. If you want trailer brakes, you need to have it wired and installed correctly, and judging by the questions/remarks, it should probably be done by a professional.
 

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Discussion Starter · #5 ·
Yes, I found out that you need a brake controller installed for the electric brakes to work. Subaru does not offer one and the Subaru dealers will not install it since it is not a Subaru offered option. The dealer told me to go to UHaul. There are 7 pin connectors that will hook into the the flat 4 installed by the dealer, with the extra wires for a brake controller. These are offered by UHaul.
 

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Discussion Starter · #6 ·
Brake controller

pnolansb9T said:
Hello,
I'm also trying to find out about wiring a brake controller into my B9T. Can this be done and how?
Yes, I found out that you need a brake controller installed for the electric brakes to work. Subaru does not offer one and the Subaru dealers will not install it since it is not a Subaru offered option. The dealer told me to go to UHaul. There are 7 pin connectors that will hook into the the flat 4 installed by the dealer, with the extra wires for a brake controller. These are offered by UHaul.
 

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Yes, you have to tie into the vehicle power for the brake controller. I found a wiring schematic PDF online which showed the trailer brake installer that they could patch into the wiring without blowing the Vehicle Body Control Unit. Apparently, the brake signal sensor draws 3 amps and that was a critical factor. If we're correct, the brake controller will be installed Monday. I'm going to tow a pop-up. But yes, can't just use adapter with signals. You must attach brake controller power supply to battery and appropriate ground. http://pdftown.com/PDF-Subaru-B9-Tribeca-2006-Service-Manual.html is where I found a complete Service Manual---FREE.
 

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Discussion Starter · #9 ·
pnolansb9T said:
Had the installer put in a Tekonsha brake controller yesterday. http://www.tekonsha.com/video/runvideo.asp?video1=p3-intro.flv

I towed the trailer home and it worked seamlessly. The mileage guage dropped to 15mpg on the highway. We're planning trips now so will let you know how it behaves.
That's great. I am having UHaul install mine (hopefully) this week.. I checked with Subaru just to make sure the install would not conflict with the Subaru warranty. I heard that BMW invalidates their warranty if you tie into the electrical system.
 
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