2018 Terrain - Trailer Wiring - Page 4 - TerrainForum.net: GMC Terrain Forum
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post #31 of 32 (permalink) Old 01-23-2020, 10:56 AM
Join Date: Aug 2019
Location: NC
Posts: 1
In reference to the wiring on the rear. I have an 2018 Equinox Premiere. I added a aftermarket hitch and the wiring was a pain for me. The Premiere uses LED lights in the rear and I believe the models below that use regular lights. I purchased a LED light kit and harness from ETrailer as I believe the LEDs use multiplexed wiring for signals. I had to run a hot wire to the battery for the adapter as the instructions led me to believe that there was not enough amperage/signals. Like the previous poster when I looked at the fuse panel behind the left wheel well all those spade connectors were empty. It makes sense to me as to why the later models have separate supplies as I bet they have LED lights on the rear also. Just stepping out on a limb here as I mainly consume all of your info over the years and it has helped me quite a bit. Hope this helps someone.
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post #32 of 32 (permalink) Old 02-25-2020, 11:08 PM
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Join Date: Jun 2018
Posts: 37
Made some progress on adding 7 pin trailer connector. Not compete but found the connections needed. Above the rear fuse box there is a harness that goes up the rear pillar to the lift gate. That had several needed signals.

First, the backup lights wire in that bundle is green/white. Will run that to a diode protected relay to isolate backup lights to the trailer.

Next is the center brake light which is violet/white. I'm going to feed that into the bluetooth brake controller's (see previous post) left and right turn signals so hazard flashers don't trigger the trailer brakes.

Then I wanted a 12V hit wire when ignition is on. Found the rear camera power is run that way. It is violet/gray. But there are 2 wires of that color in that bundle, the other being the lift gate closed switch. Anyway I will run the ignition On signal to a relay to power the brake controller and also use that power to drive a 50 Amp relay to deliver power to the trailer only when ignition is on.

Fir fuse, plan on using the empty spots in the fuse box that already have power supplied by a bus bar. 30A to the trailer power relay, 10A for backup light relay, 15A to the brake controller relay.

2 of the relays I plan to mount in the empty relay sockets.

Still plenty to do.
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