I have a factory hitch and 4-pin flat connector. I'll be installing the 7-wire plug kit from etrailer, running a wire to the front for the required power. That's all fine. But what I can't figure out is how to tap into the backup lights to supply that through to the trailer. The power module that runs the flat connector does not include backup lights.
2018 outback - what have others done?
thanks. Tom
On my crosstrek 2018 the white plug used for the tail light converter also did not include a back up signal. I ended up all the way in the right side panel at the head liner junction in order to find the wire that fed the back up lamps in the tailgate. It was a real pain in the bum. I do not know about the outback. I did talk with someone from E-Trailer and they tried to help with wiring but that was unsuccessful too. but worth a try. The outback is a more common tow vehicle than my Crosstrek.
2019 Scamp 13 standard
Thanks for responding. I have posed the question to the etrailer folks. Once you did find the wire, did you just tap into it and run to the trailer? I was also concerned whether doing so would have any negative impact on the outback wiring. Sounds like it works for yours.
I went the extra mile and used the wire tapped into the back up supply wire ( cream /white color ) and used it to energize a very small 12v relay that I then fed the relay contacts from the 10Amp fuse supplied to the tail light converter so the tail, turn, BU, and brake all feed off the 10amp fuse. But I also replaced all the outside light bulbs with LED so all together at the same time they draw 2 +amps. I too worry about extra loads and such. Why Subaru did not include the BU wire is beyond me. There is room in the white plug the converter attaches to.
2019 Scamp 13 standard
I’ve yet to dig out that trailer connector. Subaru installed the wiring when they put in the hitch. It’s puzzling but the wiring diagram in the Outback shop manual clearly shows that a wire from the backup lights circuit goes into that plug. The flat 4 does not include backup lights and the plug for that wiring doesn’t include the #3 pin that Subaru says has the backup light. If true, it’s bizarre that the wiring doesn’t at least bring that circuit along even if it is not used for the flat trailer plug.
The relay is a good idea. Which one did you use?
Confirmed what I saw on the wiring diagram. There is a backup light wire coming into the trailer connection. If Subaru had included one more pin and strand of wire on the flat 4 wiring kit, we'd all have that wire available. I realize that it's not used in the flat 4, but why run it to the trailer connection and then not use it. Madness. I'll splice in and run it in the same wire loom as the others.
is there any easy way to add a pin to the male connector to avoid splicing? Not worth a huge effort but it would be nicer.
Any small relay from the auto parts store will work. I try to find one that comes with a plug and wires attached to make wiring easier.
I just used a small relay that came in a fog/driving light kit. It had a plug and terminals I crimped on to my wires . But any small relay capable of 5-10 amp and 12 v coil. .
2019 Scamp 13 standard
I think a relay is a great idea. I note I. The descriptions of basic trailer wiring is that the box that combines the core functions also isolates the car in case there's a problem with the trailer wiring. Seems like a wise approach.
As much as I hate to say it RV wiring is not always best practice, An example is they almost all use the scotch loc's connections that are destined to fail eventually and many more examples. They are easy to install but not very permanent Attaching grounds with sheetmetal screws and such. also marginal when it comes to any wire color consistency. But it keep the price down some. and certainly is reassuring that you will never have nothing to do on your Rv.
2019 Scamp 13 standard