Why Does 4-Pin Trailer Wiring Have 5 Wires
Question:
Please help! I have a 4 pin with 5 wires, W-R-B-Y-G. I have two trailer lights to wire to... Left: R-Y-B Right: R-G-B I know the White from 4-pin is the ground. But the G/B wire from the pin and R/Y wire from the pin are confusing me. If I wire the R/Y on the left to their respective colors, then I have the Brown left alone. Where as, if I wire the G/B on the right, I am left with the Red. Im at a loss. See attached photos below. Thanks!
asked by: Paul M
Expert Reply:
Your 4-pin/5-wire wiring harness is what is called a "wishbone" type which simply means that there are two separate running light wires, one brown and one pink. This allows a separate running light wire for each side of the trailer which saves you having to run a jumper wire from one side of the trailer to the other. We offer lots of wiring items just like this, such as # A35W42B, # A20WB and # A10-4225VP, which happen to use two brown wires instead of one brown and one pink.
The functions of the 5 wires is as follows: WHITE is ground (as you stated); PINK and BROWN are for running lights; YELLOW is for LEFT stop/turn; and GREEN is for RIGHT stop/turn.
Your trailer lights may use wire colors that do not match these so this is why you always want to wire by function rather than by wire color. The lights may be labeled to tell you which wire handles what function but you can always test this with a 12V battery. You can also refer to the linked article on trailer wiring which has lots of detailed information that will help you wire the lights.
Products Referenced in This Question
Mighty Cord 4-Way Flat Trailer Connector - Wishbone Style - Trailer End - 25' Long
- Custom Fit Vehicle Wiring
- Trailer Hitch Wiring
- No Converter
- 25 Feet Long
- Custom Fit
- 4 Flat
- Mighty Cord
more information >
20 Ft 4-Way Trailer Wiring Harness - Wishbone Style - 30" Ground
- Trailer Wiring
- Trailer Connectors
- Trailer End Connector
- 11 - 20 Feet Long
- Plug and Lead
- 4 Flat
- Optronics
more information >
35 Ft 4-Way Trailer Wiring Harness - Wishbone Style - 42" Ground
- Trailer Wiring
- Trailer Connectors
- Trailer End Connector
- 31 Feet and Longer
- Plug and Lead
- 4 Flat
- Optronics
more information >
Product Page this Question was Asked From
Featured Help Information
Miscellaneous Media
Continue Researching
- Shop: Trailer Wiring
- Q&A: Wiring New 4-Way Connector on Trailer with 5 Wires
- Article: Trailer Wiring Diagrams
- Q&A: 4-Way Trailer Connector that has 5 Wires
- Shop: 35 Ft 4-Way Trailer Wiring Harness - Wishbone Style - 42" Ground
- Shop: Wesbar Wishbone Wiring Harness with 4-Pole Flat Trailer Connector - Trailer End - 18" Long
- Shop: Trailer Hitch
- Article: Wiring Trailer Lights with a 4-Way Plug (It's Easier Than You Think)
- Shop: Fifth Wheel Hitch
- Shop: Mighty Cord 4-Way Flat Trailer Connector - Wishbone Style - Trailer End - 25' Long
- Shop: Suspension Enhancement
- Shop: 20 Ft 4-Way Trailer Wiring Harness - Wishbone Style - 30" Ground
- Article: Wiring Trailer Lights with a 5-Way Plug (It's Easier Than You Think)
- Shop: Roof Rack
- Shop: CIPA Universal Deluxe Door-Mount Mirrors - Qty 2
- Shop: Mud Flaps
- Shop: Gooseneck Hitch
- Shop: Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
- Shop: WeatherTech Mud Flaps - Easy-Install, No-Drill, Digital Fit - Front and Rear Set
- Q&A: Replacing 5-Wire, 4-Way Wishbone Trailer Connector w/4-Wire Connector Causes Lights to Fail
- Search Results: receiver tube
- Search Results: wiring harness
- Search Results: c56093
- Q&A: Troubleshooting LED Lights Not Working On Trailer
- Video: Yates Rubber Boat Trailer Parts - Bow Guard - YRJONBLOCK Review
- Search Results: 4 flat 5 wire
- Search Results: bull
- Search Results: magnaflow
- Search Results: wishbone
- Article: Troubleshooting 4 and 5-Way Wiring Installations
on Wiring
Tracy W.
2/14/2024
Thank you so much for your expert advice. You have helped me save hours trying to figure out this 5 into 4 wire problem. Your explanation is so easy to understand too. Thank u, thank you. Thank you!