Trailer Lights Won't Work on 2011 Mercedes-Benz GL on Trailer With 4-Way
Question:
Hello, my GL550 towing connection with the adapter will power up UHAUL trailer lights , BUT brakes and turn signals will not function. UHAUL tested the power from auto and the adapter and says it’s fine. Same problem though, running lights work, but not the brakes or turn signals! Thank you
asked by: Rolanzo K
Expert Reply:
I'm not sure why U-haul would say it's fine when it clearly isn't, but the problem with the Mercedes is that there isn't enough power draw, so you'd need to use a lamp-out adapter:
- 7-Way to 4-Way/5-Way Trailer Adapter for Vehicles with Lamp-Out Sensors # C35FR
This will allow the trailer's brake and turn signals to recognize the signals coming from your Mercedes. If you were already using one of these adapters (I wasn't sure if you were talking about one of those or a 4-way to 7-way like # C57672), then U-Haul would need to install load resistors in the trailer for it to work.
Products Referenced in This Question
7-Way to 4-Way/5-Way Trailer Adapter for Vehicles with Lamp-Out Sensors Towing Trailers with LEDs
- Trailer Wiring
- Wiring Adapters
- Multi-Function Adapter
- 7 Round - Blade
- Plug Only
- 5 Flat
- 4 Flat
- CURT
more information >
Product Page this Question was Asked From
Curt Trailer Connector Adapter - 4-Way to 7-Way RV and 4-Way Flat
- Trailer Wiring
- Wiring Adapters
- Multi-Function Adapter
- 4 Flat
- Plug and Lead
- 4 Flat
- 7 Round - Blade
- CURT
more information >
Featured Help Information
Instructions
Miscellaneous Media
Continue Researching
- Shop: Trailer Hitch
- Q&A: Wiring for Curt Echo Mobile Wireless Brake Controller and Adding Electric Brakes to a Trailer
- Shop: Trailer Wiring
- Shop: Curt Trailer Connector Adapter - 4-Way to 7-Way RV and 4-Way Flat
- Shop: Curt Trailer Connector Adapter with Backup Alarm - 4-Way to 7-Way RV and 4-Way Flat
- Shop: Brake Controller
- Shop: etrailer Trailer Hitch Receiver - Custom Fit - Matte Black Finish - Class III - 2"
- Shop: Deka Jacketed 2 Wire, 10 Gauge, Brake Wire - per Foot
- Video: Curt Trailer Connector Adapter Installation - 2022 Hyundai Tucson
- Q&A: What is Required to Use Curt Echo Trailer Brake Controller
- Shop: Power Wire Kit for Electric Trailer Brake Controllers - 12 Gauge
- Shop: Curt Universal Wiring Kit for Trailer Brake Controllers - 10 Gauge Wires
- Shop: Hollywood Racks Destination Bike Rack for 2 Bikes - 1-1/4" and 2" Hitches - Frame Mount
- Search Results: 3500 lbs trailer axles
- Search Results: trailer hitch
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Shop: Vehicle Tow Bar Wiring
- Shop: Vehicle Air Mattress
- Article: Trailer Wiring Diagrams
- Q&A: Instructions to Wire a Trailer for Electric Brakes
- Search Results: pk12716
- Search Results: 7 pin to 4 pin
- Q&A: Recommended Trailer Wiring For A 2016 Volkswagen Tiguan
- Video: Hopkins Wiring - Trailer Connectors - HM47910 Review
- Video: Review of Curt Wiring - Wiring Adapters - C35FR
- Search Results: 37185
- Q&A: Vehicle Bulb Out Sensor Goes Off When Towing a Trailer with LED Lights
- Article: How to Choose the Right Trailer Hitch Class
- Q&A: What is the Difference Between a Class II and a Class III Hitch?
- Search Results: hitch
on Trailer Wiring
