Trailer Relay - GMC Terrain Forum
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post #1 of 4 (permalink) Old 02-18-2020, 10:46 PM Thread Starter
Join Date: Feb 2020
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Trailer Relay

Hey all, I have a 2018 terrain that doesnt have the tow package. It is an SLE 1.5L. I put a hitch on and installed the harness no problem. I havnt tried it yet to see if it works but I was told that it needs the relays installed. Which are in the back located at K1 and K3 I believe. but I don't have those slots! It looks like there not even there. Any input would be much appreciated. I am picking up my new 4 wheeler on Wednesday and i have to borrow a truck to get it because i couldnt figure this out. Thank you!
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post #2 of 4 (permalink) Old 02-19-2020, 07:12 AM
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You can test your connections by purchasing a hitch electrical tester from Harbor freight for about $5 or less. On my '18 w/o the tow package, I don't think I needed the relays either.

2018 Equinox LT1 1.5 L 4 cyl, AWD, S/R Cajun Red Tintcoat/Black

2010 Equinox LTZ 2.4 L 4 cyl, FWD, S/R Cardinal Red/Black
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post #3 of 4 (permalink) Old 02-19-2020, 01:51 PM
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Location: Lyndon, Vermont
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I installed a factory hitch on my 2018, 1.5 Equinox Premier, installed the factory harness and hooked up my small aluminum trailer. All lights worked fine with no need to address any relays. I did replace the end of the flat four harness connector with a 7 pin connector to match the trailer which in turn matches my truck. The hitch is actually designed for the 7 pin connector which is available from Curt, Polack and and others. It's a twist lock recepticle like the one used on the 2.0 equippad vehicles.
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post #4 of 4 (permalink) Old 02-20-2020, 11:11 PM
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As stated above, if you get the gm oem hitch, it comes with a harness that plugs into the connector hidden above the bumper. That harness has left and right turn relays in the wiring. Parking lights already have a relay in rear fuse box. So you are good for those connections.

But if you get aftermarket hitch that hangs under the bumper, I don't know, but my experience is writing not included. But as for adding relays in the fuse box...mine has a couple spots that are empty, but those empty slots have no contacts/wires in those positions...not an option to add relays easily up there.
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