7 Way Trailer Plug Wiring Diagram
A 7 way trailer plug connects your trailer lights to your vehicle’s power supply. The wiring powers the turn signals, brake lights, taillights, and electric brakes on your trailer. Having the correct wiring setup is crucial – an incorrect connection can lead to no lighting function or even fires.
This guide will cover:
- What’s included in a 7 way plug
- 7 Way Trailer Plug Wiring Diagrams
- How to read a 7 way trailer wiring diagram
- How to wire a 7 way plug from scratch
- Tips for testing and troubleshooting your trailer lights
Follow along to learn how to fully understand and wire your next 7 way plug.
What’s Included in a 7 Way Plug?
A 7 way trailer plug has 7 pins or wires to connect various lighting functions. Here is what each wire controls:
- Pin 1 – Electric Brakes
- Pin 2 – Tail Lights and Marker Lights
- Pin 3 – Ground (for all circuits)
- Pin 4 – Right Turn and Stop Signal
- Pin 5 – Left Turn and Stop Signal
- Pin 6 – Running Lights
- Pin 7 – Back Up Lights
So in summary, a 7 way trailer wiring system powers all of your trailer lights – turn signals, brakes, clearance, etc. The plug receives power from your vehicle to light up your trailer.
7 Way Trailer Plug Wiring Diagrams
Diagram 1:
Diagram 2:
Diagram 3:
Diagram 4:
Diagram 5:
How to Read a 7 Way Wiring Diagram
Reading schematics is key for wiring repairs and new trailer builds. Here are some tips:
- Wires are represented by lines
- Many diagrams use colors to represent each wire
- The pins are labeled clearly on diagrams (1-7)
- Power sources are marked (for example, connections to your vehicle battery)
- Ground points are marked
- Lights and other outputs are labeled
How to Wire a 7 Way Plug from Scratch
Here are step-by-step instructions to wire your own 7 way plug:
- Gather supplies – plug connector kit, wire stripper, crimper, tester. Choose 14 AWG copper wire.
- Cut each wire to length, allowing slack. Strip about 0.5″ insulation from ends.
- Crimp pins onto wire ends. Follow diagram coloring for circuit order.
- Insert pins snugly into plug body according to diagram.
- Ground white wire to trailer frame.
- Connect color wires to matching lights via splicing:
- Yellow: left turn/brake
- Green: right turn/brake
- Brown: taillights
- Red: stop and dash lights
- Test plug by connecting to vehicle, turning signals, brakes, and checking trailer light function.
Be sure to use adequate gaffer tape or heat shrink connections to protect wiring. Repeated trailering will expose connections to elements, so waterproofing is a must.
With this full wiring tutorial, your custom plug should operate safely for hauling.
Tips for Testing and Troubleshooting
Issues can arise over time with trailer wiring as connections come loose or corrode. Here are helpful tips for testing:
- Give the plug, wires, and lights a visual inspection for corrosion or damage
- Check that the trailer ground wire has a solid connection
- Use a circuit tester to check for continuity in each pin
- Gently tug on wires to test for loose connections
- Plug in plug to test function of all lights
Finding the root of electrical issues takes patience. Work through each wire systematically. It’s likely a loose ground or single damaged wire connection.
Conclusion
7 way trailer wiring powers all of your trailer lights for safe travel. This guide reviewed complete 7 way trailer plug wiring diagrams, function of each wire, step-by-step installation, and troubleshooting tips.
With the foundation here, you can confidently wire a new plug or repair your existing 7 way trailer wiring. Take it slow, follow wiring schematics, and be diligent with testing connections. Driving at night will be much less stressful knowing you have reliable lighting for other drivers to see.
Safe travels on the roads!
