Best Way To Add 7-Way To 2017 Subaru Outback
Updated 09/26/2025 | Published 04/29/2025
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Question:
Hi, ive got a 2017 Subaru outback, and want to install a hitch and wiring for towing a small RV popup. The RV has a 7 pin flat wiring harness. The wiring harness in the rear of the Subaru connector R79 for trailer connection has a 12V line pin 1 to fuse 28. ive read your article about going from a 4 pin Etrailer item 118467 to a 7 blade item ETBC7 connector, and find several articles about connecting a brake controller. I dont need the brake controller but need the battery charging. 2 questions: 1. is the 12V line in the R79 Subaru connector suitable for charging a battery in an RV? 2. does etrailer sell a wiring harness that goes from the Subaru connector R79 directly to a 7 wire flat connector, including the 12V wire connection? Or do i have to first do the 4 wire harness and then get the 4 to 7 wire converter? thanks in advance
asked by: Mike S
Expert Reply:
Hello Mike, thanks for reaching out. You are on the right track with the # 118467 and # ETBC7 kits. That is exactly what you will need to add a 4-flat a 7-way to your 2017 Subaru Outback. This includes the 12v power wire you can use to run a charge to your camper. There is no kind of custom harness for the R79 connector, so the # ETBC7 will definitely be your best bet. That will include all the necessary wires for a brake controller, which you do not have to add now. I would probably run the wires anyway and cap them off just in case you need them in the future.
Please let me know if there is anything else I can do to help.
Product Page this Question was Asked From
7-Way RV Upgrade Kit for Trailer Brake Controller Installation - 12 Gauge Wires
- Accessories and Parts
- Trailer Brake Controller
- Installation Kits
- etrailer
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Jesse M.
9/26/2025
Hey Mike, did the ETBC7 kit work out for charging your RV battery? I'm asking because your experience could help others looking to set up their Subaru for towing.