2011 Subaru Outback Wagon Trailer Wiring | etrailer Lowest Price Trailer Wiring Guarantee. Installation instructions and lifetime expert support on all purchases of 2011 Subaru Outback Wagon Trailer Wiring. Order online at etrailer 2011 Subaru Outback Hitch Wiring | Harnesses, Adapters Subaru Outback 2011, Plug-In Simple!® Towing Wiring Harness with 4-Flat Connector by Hopkins®. This product is made of high-quality materials to serve you for years to come. Designed using state-of-the-art technology and with customers..