Installing 7-Way and 4-Way Connectors on a 2015 GMC Acadia
Published 06/07/2018 >
Question:
I have a wiring harness pre installed. And ordered a HM40975. Jon G suggested part 118271 to connect the 2. My question is, will part #118271 run the 7 pole and the 4 flat on part HM40975? Or just the 7 pole? Thank you.
asked by: Nathan S
Helpful Expert Reply:
The Hopkins # HM40975 that you referenced plugs into a US Car Connector (see attached picture). This typically will replace a factory 7-Way on a vehicle so if your 2015 GMC Acadia didn't come with a 7-Way you might not have that connector. If it does exist though it will be located somewhere around the trailer hitch.
If you don't have the US Car Connector but you would like fully functioning 7-Way and 4-Way connectors then we do have a solution for you. Simpy install the T-One Vehicle Wiring Harness # 118271 (if you have the factory tow package) and then swap out the included connector with the Hopkins # HM40975 that you referenced. To keep from drilling into your vehicle or trailer hitch use the No-Drill Mount Bracket # 18140 as well.
Attached are some installation videos for you to check out.
Product Page this Question was Asked From
7- and 4-Pole Trailer Connector Socket w/ Mounting Bracket - Vehicle End
- Custom Fit Vehicle Wiring
- Trailer Hitch Wiring
- Vehicle End Connector
- No Converter
- No Tow Package
- 4 Flat
- 7 Blade
- Plug Only
- Pollak
more information >
Featured Help Information
Miscellaneous Media
Continue Researching
- Shop: Trailer Wiring
- Search Results: 13591
- Search Results: 2793
- Shop: Trailer Hitch
- Shop: 7-Way RV Upgrade Kit for Trailer Brake Controller Installation - 12 Gauge Wires
- Shop: Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
- Q&A: Availability of EcoHitch Front Hitch Installation Video With Active Air Dam Removal for 2024 F-150
- Shop: Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
- Shop: Curt Trailer Hitch Receiver - Custom Fit - Class III - 2"
- Shop: etrailer Adjustable 2-Ball Mount - 2" Hitch - 6" Rise, 6" Drop - 10K
- Shop: Curt Class III Ball Mount with 2" Ball - 6" Drop - 7,500 lbs
- Shop: Curt Ball Mount - 6" Rise, 8" Drop - 11-1/2" Long - 5,000 lbs
- Search Results: hopkins 40975
- Search Results: night hawk
- Search Results: etrailer tow bar
- Q&A: Plug In Tow Bar Wiring and Trailer Wiring Harness at the Same Time on a 2017 GMC Terrain
- Video: Set up: Curt T-Connector Vehicle Wiring Harness for Factory Tow Package on a 2015 GMC Terrain
- Search Results: 13615
- Search Results: 13416
- Video: How to Install the EcoHitch Hidden Trailer Hitch Receiver on a 2017 Jeep Renegade
- Video: Installing the Curt Trailer Hitch Receiver on a 2025 Toyota RAV4
- Video: Installing the Curt T-Connector Vehicle Wiring Harness on a 2023 Lincoln Aviator
- Video: 2023 Ford F-150 EcoHitch Hidden Front Mount Trailer Hitch Receiver: Complete Installation
- Video: How to Install the Curt Trailer Hitch Receiver on a 2015 Jeep Renegade
- Video: Trailer Wiring Harness Installation - 2014 GMC Terrain
- Q&A: Availability of Hitch and Wiring for 2025 Toyota RAV4 Hybrid XLE Premium
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Article: Trailer Wiring Diagrams
- Article: Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)
- Q&A: Do You Have the Replacement Hardware for My Curt Hitch?





Nathan S.
6/7/2018
I have a wiring harness pre installed. And ordered a HM40975. Jon G suggested part 118271 to connect the 2. My question is, will part #118271 run the 7 pole and the 4 flat on part HM40975? Or just the 7 pole? Thank you.