If you’re planning to hitch a trailer to your vehicle, you must know the importance of having a proper wiring setup. Without it, you won’t be able to power up the brake lights, turn signals, and other electrical components of the trailer. In this article, we’ll outline everything you need to know about wiring a trailer plug. We’ll cover the basics, different types of plugs, tools and materials, step-by-step guide, and FAQs to ensure you have a smooth and successful setup.
Basics of Trailer Wiring
Before we dive into the specifics, let’s start with the fundamentals. A trailer wiring system consists of two components – the vehicle-side connector and the trailer-side connector. The vehicle-side connector, often referred to as the tow vehicle connector, is usually installed in the car’s rear and connected to the trailer’s plug. Alternatively, some vehicles come with built-in connectors that allow for a simple plug-and-play setup.
The trailer-side connector, on the other hand, is attached to the trailer and receives its power from the tow vehicle. The most common types of trailer connectors are 4-pin, 5-pin, 6-pin, 7-pin, and 7-way RV blade. Each type of plug has a different number of pins, and the number of pins will determine how many electrical components can be powered.
4-Pin Trailer Connector
The 4-pin trailer connector is commonly used for small trailers and utility vehicles that have few or no lights. It has four pins that provide power to the brake lights, turn signals, and taillights. The pins are as follows:
| Pin | Function |
|---|---|
| 1 | Ground |
| 2 | Left turn/brake light |
| 3 | Right turn/brake light |
| 4 | Taillight |
For a typical 4-pin setup, the white wire connects to the ground, and the yellow, green, and brown wires connect to the left turn/brake light, right turn/brake light, and taillight, respectively.
5-Pin Trailer Connector
The 5-pin trailer connector is similar to the 4-pin connector but with an additional pin for the reverse light. It’s ideal for small trailers with backup lights. The pins are as follows:
| Pin | Function |
|---|---|
| 1 | Ground |
| 2 | Left turn/brake light |
| 3 | Right turn/brake light |
| 4 | Taillight |
| 5 | Reverse light |
For a typical 5-pin setup, the white wire connects to the ground, and the yellow, green, brown, and blue wires connect to the left turn/brake light, right turn/brake light, taillight, and reverse light, respectively.
6-Pin Trailer Connector
The 6-pin connector is less common but still widely used. It’s typically found on horse trailers and larger utility trailers that require more wiring connections. The pins are as follows:
| Pin | Function |
|---|---|
| 1 | Ground |
| 2 | Left turn/brake light |
| 3 | Right turn/brake light |
| 4 | Taillight |
| 5 | Electric brakes |
| 6 | 12V+ auxiliary power |
For a typical 6-pin setup, the white wire connects to the ground, and the yellow, green, brown, blue, and black wires connect to the left turn/brake light, right turn/brake light, taillight, electric brakes, and 12V+ auxiliary power, respectively.
7-Pin Trailer Connector
The 7-pin trailer connector is the most common type of plug and can accommodate a wide range of trailers. It’s typically found on RVs, boat trailers, and larger utility trailers. The pins are as follows:
| Pin | Function |
|---|---|
| 1 | Ground |
| 2 | Left turn/brake light |
| 3 | Right turn/brake light |
| 4 | Taillight |
| 5 | Electric brakes |
| 6 | 12V+ auxiliary power |
| 7 | Backup lights |
For a typical 7-pin setup, the white wire connects to the ground, and the other wires connect to the same components as the 6-pin, with the addition of the backup lights.
7-Way RV Blade Trailer Connector
The 7-way RV blade trailer connector is similar to the 7-pin connector but with a single lock-in tab for secure connection. It’s commonly used on RVs and travel trailers. The pins are as follows:
| Pin | Function |
|---|---|
| 1 | Ground |
| 2 | Electric brakes |
| 3 | Taillight |
| 4 | Battery power |
| 5 | Left turn/brake light |
| 6 | Right turn/brake light |
| 7 | Backup lights |
For a typical 7-way RV blade setup, the white wire connects to the ground, and the other wires connect to the same components as the 7-pin, with the addition of the battery power.
Tools and Materials
Now that you have an idea about the different types of trailer plugs and their functions, it’s time to gather the necessary tools and materials. Here’s a list of items you’ll need:
- Trailer wiring kit (make sure it’s compatible with your type of plug)
- Wire cutters/strippers
- Crimping tool
- Electrical tape
- Heat shrink tubing (optional)
- Screwdriver
Step-by-Step Guide
Here’s a step-by-step guide to wiring your trailer plug:
Step 1: Prepare the Vehicle-Side Connector
Locate the vehicle’s rear wiring harness and identify the wires that correspond to the pins on the trailer plug. Use the wire cutters/strippers to strip away the insulation from the wires, leaving a clean, exposed end.
Step 2: Attach the Trailer Wiring Kit
Take the trailer wiring kit and match the colors of the wires to the corresponding pins on the plug. Crimp the wires onto the pins, making sure they are secure and tight. You can also use heat shrink tubing for added protection.
Step 3: Test the Connection
Before you start routing the wires, test the connection by plugging the connector into the trailer’s plug. Turn on the vehicle’s headlights, brake lights, and turn signals to ensure everything is working correctly.
Step 4: Route the Wires
Once everything is working, start routing the wires along the trailer frame, securing them with electrical tape or zip ties. Be sure to keep the wires away from any moving parts or sharp edges that can damage the insulation.
Step 5: Attach the Trailer-Side Connector
Finally, attach the trailer-side connector to the end of the wiring harness, crimping the wires onto the pins and securing them with electrical tape or heat shrink tubing. Plug the connector into the tow vehicle, and you’re ready to hit the road!
FAQs
What gauge wire should I use for my trailer wiring?
The gauge of wire you need depends on the amperage draw of the electrical components of your trailer. As a general rule, you should use 16-gauge wire for taillights and running lights, 14-gauge wire for turn signals, and 12-gauge wire for electric brakes and battery charging.
Can I wire my trailer without a kit?
While it’s possible to wire your trailer without a kit, it’s not recommended. Trailer wiring kits come with everything you need to make a correct and safe connection, including specific wires, connectors, and instructions. It’s worth the small investment to ensure a successful setup.
How do I troubleshoot trailer wiring problems?
If you’re having issues with your trailer wiring, there are a few things you can check. First, make sure the connectors are clean and free of corrosion. Second, check the fuses and relays in your vehicle’s electrical system to ensure they’re in working order. Finally, use a multimeter to test the voltage at different points along the wiring to pinpoint the issue.
What’s the difference between a 4-pin and 7-pin trailer connector?
A 4-pin trailer connector is designed for smaller trailers with fewer electrical components, while a 7-pin connector is suited for larger trailers with electric brakes, battery charging, and other powered accessories. The number of pins on the connector determines the number of available electrical circuits.
How often should I inspect my trailer wiring?
You should inspect your trailer wiring before every use to ensure everything is functioning correctly. Make sure the connections are secure and free of corrosion, and that the wires are not damaged or exposed. Regular inspections can prevent costly repairs and ensure your safety on the road.
