Troubleshooting 4-Way Wiring Relays Wont Install on 2018 GMC Terrain
Updated 11/22/2022 | Published 11/19/2022
Products Featured in This Question
Question:
I have a 2018 terrain. I installed the wiring harness per video but the relays dont snap into the block. What else do I need?
asked by: Roy
Expert Reply:
It sounds like you're installing the Curt # C56375 on your 2018 GMC Terrain. This is designed for the factory tow package. Since your relays don't snap into the K1 and K3 positions it sounds like the terminals are missing from the relay cavity. This means you need the T-One Vehicle Wiring Harness # 118764 instead. This wiring harness is designed for the Terrain without the factory tow package, and no relays are required.
Product Page this Question was Asked From
Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
- Custom Fit Vehicle Wiring
- Trailer Hitch Wiring
- Vehicle End Connector
- No Converter
- No Tow Package
- 4 Flat
- Plug and Lead
- Plug-In
- CURT
more information >
Featured Help Information
Instructions
Miscellaneous Media
Continue Researching
- Q&A: Looking for Class II Hitch for 2025 Toyota Sieanna XLE
- Q&A: Is Curt RVi Series Shadow 2 Compatible With 2025 Jeep Gladiator
- Q&A: Recommended Trailer Wiring Harness For A 2022 Chevrolet Equinox
- Q&A: Recommended Trailer Hitch for a 2020 Hyundai Palisade
- Q&A: Trailer Hitch Recommendation for a 2020 Hyundai Palisade
- Q&A: Correct Trailer Hitch for a 2020 Hyundai Palisade
- Q&A: What is the Best Grease for Trailer Bearings
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Article: Wiring Trailer Lights with a 4-Way Plug (It's Easier Than You Think)
- Article: Tow Bar Wiring Overview
- Article: Trailer Wiring Diagrams
- Article: How to Choose the Right Trailer Hitch Class
- Article: Routing the Power Wire for a Trailer Wiring Harness
- Article: Choosing the Right Suspension Kit for Your Truck and Trailer