Are you planning to tow a trailer? If yes, then you must know how to properly wire your trailer. In this article, we will discuss the 7 spade trailer wiring diagram, which is one of the most common wiring systems for trailers.
What is a 7 spade trailer wiring diagram?
A 7 spade trailer wiring diagram is a wiring configuration that uses a 7-pin connector to transfer power between the vehicle and the trailer. The 7-pin connector includes seven wires that connect the trailer’s electrical system to the vehicle’s electrical system.
The 7 wires of the 7-pin connector are:
| Pin | Wire Color | Function |
|---|---|---|
| 1 | White | Ground |
| 2 | Blue | Brake Controller Output |
| 3 | Green | Right Turn/Brake Lights |
| 4 | Red | Left Turn/Brake Lights |
| 5 | Brown | Tail and License Lights |
| 6 | Yellow | Reverse Lights |
| 7 | Black | Battery Charge and Auxiliary Power |
Now, let’s take a closer look at each wire and its function.
White Wire: Ground
The white wire is the ground wire, which provides a path for electrical current to flow back to the vehicle’s battery. The ground wire is essential for any electrical circuit, as it completes the circuit and allows electricity to flow.
Make sure that the ground wire is securely connected to the vehicle’s metal frame or chassis, and to the trailer’s frame or chassis.
Blue Wire: Brake Controller Output
The blue wire is used to connect the brake controller to the trailer’s brakes. When the vehicle’s brakes are applied, the brake controller sends a signal through the blue wire to activate the trailer’s brakes.
If your trailer has electric brakes, you must install a brake controller in your vehicle and connect it to the trailer using the blue wire.
Green Wire: Right Turn/Brake Lights
The green wire is used to connect the vehicle’s right turn signal and brake lights to the trailer’s right turn signal and brake lights. When you activate the right turn signal or apply the brakes, the green wire sends a signal to the trailer’s lights to turn on.
Red Wire: Left Turn/Brake Lights
The red wire is used to connect the vehicle’s left turn signal and brake lights to the trailer’s left turn signal and brake lights. When you activate the left turn signal or apply the brakes, the red wire sends a signal to the trailer’s lights to turn on.
Brown Wire: Tail and License Lights
The brown wire is used to connect the vehicle’s tail lights and license plate light to the trailer’s tail lights and license plate light. The tail lights are always on when the headlights are on, while the license plate light illuminates the trailer’s license plate at night.
Yellow Wire: Reverse Lights
The yellow wire is used to connect the vehicle’s reverse lights to the trailer’s reverse lights. When you shift your vehicle into reverse gear, the yellow wire sends a signal to the trailer’s reverse lights to turn on.
Black Wire: Battery Charge and Auxiliary Power
The black wire is used to connect the vehicle’s battery to the trailer’s electrical system. This wire provides power to the trailer’s battery, which can be used to operate accessories such as interior lights and hydraulic lift gates.
If your trailer does not have a battery, you can still use the black wire to power auxiliary accessories.
Frequently Asked Questions (FAQ)
Q: What type of vehicles can use a 7 spade trailer wiring diagram?
A: A 7 spade trailer wiring diagram can be used with any vehicle that has a 7-pin connector. This includes most trucks, SUVs, and vans.
Q: Do I need to install a brake controller for my trailer?
A: If your trailer has electric brakes, you must install a brake controller in your vehicle and connect it to the trailer using the blue wire. This is a legal requirement in most states.
Q: How do I test my trailer’s wiring?
A: To test your trailer’s wiring, you can use a multimeter or a test light. Connect the tool to each wire of the 7-pin connector and check if the corresponding light or sound is activated in the tool. If a wire does not work, check if there is a loose connection or a broken wire.
Q: Can I use a 7 spade trailer wiring diagram for a trailer with hydraulic brakes?
A: No, a 7 spade trailer wiring diagram is only suitable for trailers with electric brakes. For trailers with hydraulic brakes, you need a different wiring system that includes a brake line and a brake actuator.
Q: Do I need to use a specific type of wire for my trailer’s wiring?
A: Yes, you should use a wire that is specifically designed for trailer use, such as SAE J1128 or SAE J1127. These wires are rated for outdoor use and are resistant to water, heat, and abrasion.
Q: How can I prevent my trailer’s wiring from getting damaged?
A: To prevent your trailer’s wiring from getting damaged, you should keep it clean, dry, and secured. Make sure that the wires are not exposed to sharp edges, moving parts, or corrosive substances. You can use loom, conduit, or zip ties to protect the wires and keep them organized.
Conclusion
Wiring your trailer using a 7 spade trailer wiring diagram is not difficult, but it requires attention to detail and proper tools. Make sure that you follow the wiring diagram carefully and test your wiring before towing. By doing this, you can ensure that your trailer’s electrical system works properly and safely.
