Troubleshooting LED Trailer Lights Not Working Right When Plugged Into 2020 Mercedes-Benz GLS 450
Updated 07/02/2021 | Published 07/01/2021
Question:
My 2020 GLS 450 was installed with the Stealth hitch with wiring. The trailer LED lights won’t function properly unless the running/headlights are on. Which adapter would you recommend? Is this a common issue with Mercedes? Thank you.
asked by: Byron
Helpful Expert Reply:
It is pretty common for trailer wiring harnesses on Mercedes-Benz vehicles like your 2020 Mercedes-Benz GLS 450 and other German vehicles to have issues with trailers that have LED trailer lights.
The correct adapter to fix this is the 7-Way to 5-Way/4-Way Trailer Adapter for Vehicles with Lamp-Out Sensors Towing Trailers with LEDs # C35FR if your trailer has a 4-way or 5-way flat connector, or the # 20142 if your trailer has a 7-way connector.
These adapters have built in resistors to help your Mercedes detect that a trailer is connected and make sure that it sends power to all of the lighting functions.
Product Page this Question was Asked From
7-Way to 4-Way/5-Way Trailer Adapter for Vehicles with Lamp-Out Sensors Towing Trailers with LEDs
- Custom Fit Vehicle Wiring
- Wiring Adapters
- Universal Fit
- 7 Blade to 4 Flat
- 7 Blade to 5 Flat
- Plug Only
- CURT
more information >
Featured Help Information
Miscellaneous Media
Continue Researching
- Search Results: led trailer adapter
- Search Results: trailer door parts
- Shop: Trailer Wiring
- Video: A Closer Look at the 7-Way Trailer Adapter for Towing Trailers with LED Lights
- Video: Curt 7-Way to RV Socket LED Circuit Tester Review
- Shop: 7-Way Trailer Adapter for Towing Trailers with LED Lights
- Shop: Curt 7-Way to RV Socket LED Circuit Tester - Vehicle End
- Shop: Rubber Window Edge Weather Strip for RVs - Press In - 20' Long x 1/2" Tall
- Search Results: trailer jack
- Shop: 7-Way to 4-Way/5-Way Trailer Adapter for Vehicles with Lamp-Out Sensors Towing Trailers with LEDs
- Shop: etrailer Boat Trailer Jack w/ Wheel - Sidewind - Swivel - 11" Lift - 1,200 lbs
- Shop: Dutton-Lainson Pull Pin, Easy Swivel Trailer Jack w/ Wheel - Sidewind - 10" Lift - 1,000 lbs
- Shop: etrailer Boat Trailer Jack w/ Dual Wheel - Sidewind - Swivel - 10-3/8" Lift - 1,500 lbs
- Q&A: What is the Difference Between a Class II and a Class III Hitch?
- Search Results: trailer hitch
- Shop: Trailer Hitch
- Article: Trailer Wiring Diagrams
- Q&A: What is the Difference Between a 4-Way and 7-Way Trailer Connector
- Video: How to Choose a Trailer Brake Controller
- Search Results: trailer wiring
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Article: Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)
- Search Results: trailer tires and wheels
- Shop: Suspension Enhancement
- Video: Clean Up Your Trailer Wiring
- Q&A: Lug Nut Torque Chart for Trailer Wheels
- Article: How to Measure for Trailer Hitch Drop
- Shop: Brake Controller
- Video: Curt T-Connector Vehicle Wiring Harness Review C56040
- Q&A: Installation Time for Blue Ox BX1128 Flat Tow Base Plate Kit for 2016 Jeep Grand Cherokee
on Custom Fit Vehicle Wiring
