One Side of Trailer Lights Not Working With C35FR
Question:
I purchased the TR20141 from etrailer and when I installed the plug on my 2021 Mercedes Sprinter I received an error on the dash display indicating an issue with the right trailer turn indicator. I hooked up my LED lights and the left side works, break and all. But, the right side,, not. Any suggestions?? Thanks!
asked by: Thomas B
Expert Reply:
Since one side of the trailer lights is working fine, it leads me to believe the issue is something other than the 7-Way to 5-Way/4-Way Trailer Adapter for Vehicles with Lamp-Out Sensors Towing Trailers with LEDs # C35FR.
If this were the issue (if the adapter were not working as intended), then it would reason that there would be faults on both sides with your vehicle. My best guess is that the issue is with the actual trailer wiring, or possibly the connector. Since you have a 2021 Sprinter, it is unlikely to be the vehicle, so let's rule that out. So what you want to do is first just take a look at your trailer connector for corrosion, which can be green or white in color. A build-up of corrosion can interfere with the signals getting through the connectors so if it is present you are going to need to replace it with 4-Flat # HM48114.
You will also want to test the signals coming out of your 7-way with a circuit tester like # PTW2979, and if those are bad you know the issue is with the trailer wiring so you'll need to inspect it closely for any broken, crimped, or damaged wiring. Finally, make sure your grounds are attached to bare metal surfaces and free of any paint, dirt or corrosion.
I have added a link below to a troubleshooting help article I also recommend taking a look at.
Products Referenced in This Question
Hopkins Endurance Easy-Pull Harness with 4-Pole Flat Trailer Connector - Trailer End - 12" Long
- Trailer Wiring
- Trailer Connectors
- Trailer End Connector
- 0 - 5 Feet Long
- Plug and Lead
- 4 Flat
- Hopkins
more information >
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
- Trailer Wiring
- Wiring Adapters
- Multi-Function Adapter
- 7 Round - Blade
- Plug Only
- 5 Flat
- 4 Flat
- CURT
more information >
Continue Researching
- Video: Trailer Hitch Installation - 2016 Mercedes-Benz Sprinter 3500
- Shop: Trailer Wiring
- Article: Trailer Wiring Diagrams
- Shop: Cordless Circuit Tester
- Shop: Trailer Connector Adapter w/ Lamp-Out Sensor Bypass - 7-Way RV to 7-Way RV - Vehicle End
- Shop: Tekonsha OEM Replacement Vehicle Wiring Harness w Brake Controller Adapter - 7 Way Trailer Connector
- Shop: Trailer Hitch
- Shop: Vehicle Tow Bar Wiring
- Shop: Roadmaster 4-Diode Universal Wiring Kit for Towed Vehicles - 4-Way Flat Connectors
- Shop: Curt Universal Tail Light Wiring Kit for Towed Vehicles
- Shop: Roadmaster 4-Diode Universal Wiring Kit for Towed Vehicles - 7-Wire to 6-Wire Straight Cord
- Video: Choosing the Right Trailer Wiring
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Search Results: 44649
- Q&A: What is the Difference Between a Class II and a Class III Hitch?
- Shop: Curt Powered Tail Light Converter with 4-Pole Flat Trailer Connector
- Article: How to Choose the Right Trailer Hitch Class
- Q&A: What is the Difference Between a 4-Way and 7-Way Trailer Connector
- Video: Tow Ready 4-Pole Mounting Bracket Installation
- Search Results: 68149
- Search Results: 25580
- Q&A: Recommended Lithium Battery Compatible Power Converter For Parallax 7355
- Video: Choosing the Right Brake Controller
- Shop: Brake Controller
- Video: Draw-Tite Max-Frame Trailer Hitch Installation - 2019 Chevrolet Equinox
- Q&A: Replacement Clearance Lights Needed for GLO-BRITE 122R and 122Y Lights
- Search Results: dust cap
- Shop: Fifth Wheel Hitch
- Article: My Trailer Hitch Doesn't Fit
- Video: Tekonsha T-One Vehicle Wiring Harness Installation - 2020 GMC Terrain 118764