Troubleshooting Function of Additional Trailer Side Marker/Signal Lights
Updated 06/25/2018 | Published 06/22/2018
Products Featured in This Question
Question:
Hi, I recently rewired my trailer and added dual-function three-wire lights on the fenders running and signal and used the converter 118158 to separate the signals so those don’t come on under braking. The brake wire from the converter is just capped and taped up. I’m having a problem when I signal where the tail lights on my truck alternate left and right and the wrong fender signal on the trailer flashes. The rear signals on the trailer still combined with brake work mostly as intended. I double checked all of the wiring, and it’s as it should be, but it seems like there’s some backfeeding. Do I need to install diodes? If so, where? Thanks!
asked by: Zach L
Expert Reply:
The problem you're having with your new wiring could be related to the ground, especially since it sounds like you may have added more lights than were originally on the trailer. It often happens that weird behavior from trailer lights results from a loose, corroded or insufficient ground connection.
First make sure that each individual light's ground is made to clean bare metal. Some lights like # TLL12RK use a wired ground (white wire with ring terminal) while others like # ST52AA ground through their mounting post. Either way, the ground must be made to clean bare metal that is free of paint, primer, rust, grease, etc.
If making these new ground connections does not correct the issue then check the main trailer ground where it connects to the trailer frame. Sand/clean that spot to expose clean bare metal and make your new ground connection.
You can refer to the linked articles on trailer wiring for additional information.
Product Page this Question was Asked From
Tail Light for Trailers Over 80" Wide - 7 Function - Incandescent - Square - Passenger Side
- Trailer Lights
- Tail Lights
- Rear Clearance
- Rear Reflector
- Side Marker
- Side Reflector
- Stop
- Tail
- Turn
- Square
- Surface Mount
- Non-Submersible Lights
- Incandescent Light
- 6-1/8L x 4-9/16W Inch
- Red
- Optronics
more information >
Featured Help Information
Miscellaneous Media
Continue Researching
- Q&A: How Much Do the Rock Tamers Heavy-Duty, Adjustable Mud Flap System for 2" Hitches Weigh?
- Q&A: Is My 2016 Honda Pilot Trailer Wiring 7-way or Only 4-way?
- Q&A: Replacement For Grease Seal 32374 For Trailer
- Q&A: Spare Wheel and Tire for Aluma Trailer 6310H
- Q&A: What Is The Weight And Specs Of Rapid Hitch Adjustable Ball Mount AM3411
- Q&A: Mounting Plate Dimensions and Bolt Holes on Ultimate Trailer Jack # 322-RDJ-2K
- Q&A: What Is The Shoe In A Schwintek Slide Out System And What Does It Do
- Article: Trailer Wiring Diagrams
- Article: Slipper Spring Trailer Suspension System Review
- Article: 7 Common Questions Everyone Has About Trailer Tires
- Article: How to Service An RV Air Conditioner
- Article: How to Bleed Your Trailer Surge Brakes
- Article: Trailer Drum Brakes vs. Disc Brakes: Making the Decision
- Article: Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)