Troubleshooting Curt C56020 Not Working Correctly On 2006 Ford E350 Passenger Van
Updated 09/02/2025 | Published 08/09/2025
Question:
To whom concern, I brought a trailer wire harness from you all for my 2006 Ford E350 super duty passenger van and when I hook trailer wire to van the brake lights and trailer lights goes out but when I unhook trailer connectors on passenger side of van trailer lights comes on
asked by: Armstead R
Expert Reply:
Hello Armstead, thanks for reaching out. It sounds like the plugs/connectors on the Curt # C56020 wiring harness are not seated all the way. This is actually kind of common with these harnesses and it would explain why the lights are working that way. Try unplugging both sides and plugging them back in firmly to see if the problem goes away. Make sure the vehicles connectors are not bent or rusted. This wiring harness does not have a converter module so there really aren't any other troubleshooting steps for these. If its plugged in it should work.
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
- Hidden
- CURT
more information >
Featured Help Information
Instructions
Continue Researching
- Shop: Vehicle Sway Bars
- Shop: Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
- Shop: Trailer Wiring
- Article: Brake Controller Installation on a Ford Full-Size Van
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Q&A: Parts Needed To Add 7-Way Connector To 2011 Ford E-350 Without Factory Towing Package
- Q&A: Brake Controller Wiring Harness and Air Bags for 2014 E-450
- Q&A: How to Use a Curt Echo Wireless Brake Controller on a Vehicle w/a 4-Way Connector
- Q&A: Replacement Wiring Harness for Cummins Onan 4KY-6747R Generator
- Q&A: Location of Brake Controller Connector on 2009 Ford F350
- Q&A: Brake Controller Installation in 2019 Ford Ranger
- Q&A: Recommended Hitch for a 2026 Kia Sportage
- Article: Brake Controller Installation: Starting from Scratch
- Article: Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)
- Article: Wiring Trailer Lights with a 4-Way Plug (It's Easier Than You Think)
- Article: Trailer Wiring Diagrams
- Article: What Do I Need To Tow A Trailer?
Jesse M.
9/2/2025
Hey Armstead, did re-seating the connectors on your wiring harness solve the issue with the brake and trailer lights? I'm asking because your experience could help others who might face a similar problem.