Wired the tailgate release to AUX 6 last night and it's a pretty convenient and inexpensive mod. This is the kit sold here by Brendon Webster and was complete with great detailed instructions. Couple of things to share...Ford did a great job of hiding the AUX wiring. There are two sets under the hood and a set above the passenger kick panel fuse box location. One of the sets under the hood will take a bit of exploring to find but you should see it as it's only partially wrapped however, the bundle above the fuse box is another story - (really need to access by disconnecting the glove box stops and lowering the glove box). Mine was completely wrapped in the harness and not easy to find, but be patient and you will eventually find it. Tight area with lots of sharp edges 
. Also, the 2018 Supplement has (for my 2018 anyways) the incorrect wiring color codes and (thanks Brendan) for including the alternate wiring color codes in your instructions.
All in all, great inexpensive mod and something Ford should have included from factory. Works identical to the "Trunk Release" in my GT350 (with same safe guards, etc.) Highly recommend and now I know where the AUX wires are for upcoming mods!!
. Also, the 2018 Supplement has (for my 2018 anyways) the incorrect wiring color codes and (thanks Brendan) for including the alternate wiring color codes in your instructions. All in all, great inexpensive mod and something Ford should have included from factory. Works identical to the "Trunk Release" in my GT350 (with same safe guards, etc.) Highly recommend and now I know where the AUX wires are for upcoming mods!!
