Trailer wiring on 07 equinox

[Kevyrev]

I already purchased an attwood submersible light kit for my boat trailer and was going to try to wire the vehicle portion to my brake lights.
I researched and found that there is a harness behind jack storage compartment that I'd have to buy for an additional $25 and have to install 3 fuses and a relay. This does seem like an easy install but I'm not crazy about having the wiring harness hang out where you have to shut the rear hatch door on it. Also don't want to spend $25 on something I already have with my kit.
My question is, is it possible or somewhat easy to wire my included harness into the brake lights without being too much of a headache, has anyone done this. Also I'd rather have the wires down by my hitch instead of coming out under the hatch door.

 

[cavell]

Just got my 06 and it has hitch. And there is a plug next to receiver. It is fed from module in jack area. If this is factory why can't you copy the layout? grab the bits at a boneyard? Found a nox at boneyard with hitch and a factory sub too. Pioneer? Heard the pioneer setup is rather odd?

 

[Barthos]

What's odd about the Pioneer setup? What's a good alternative then?