A Bargman plug is a standard trailer plug used to connect the electrical wiring of a trailer to that of a tow vehicle. The 7-way Bargman plug is the most common plug used in North America. It has seven pins that are used for different electrical functions. In this article, we will explore the basics of 7-way Bargman plug wiring diagram and how it works.
What is a 7-way Bargman Plug Wiring Diagram?
A 7-way Bargman plug wiring diagram shows how the seven pins of the Bargman plug are used for different electrical functions. The seven pins are identified by numbers from 1 to 7, and each pin is assigned a specific function. By following the wiring diagram, you can connect the electrical wiring of your trailer to that of the tow vehicle, ensuring that all electrical functions work properly.
It is essential to properly wire the Bargman plug to ensure safe and reliable towing. In the next sections, we will explore the seven pins and their functions in detail.
Understanding the Seven Pins of a 7-way Bargman Plug
The following table shows the seven pins of a 7-way Bargman plug and their functions:
| Pin Number | Function |
|---|---|
| 1 | Left turn signal and brake |
| 2 | Reverse lights |
| 3 | Ground |
| 4 | Tail lights |
| 5 | Right turn signal and brake |
| 6 | Brake controller output |
| 7 | 12V power supply |
Pin 1: Left Turn Signal and Brake
Pin 1 of the Bargman plug is used for the left turn signal and brake lights of the trailer. When the tow vehicle’s left turn signal is activated, power is sent through this pin to the left turn signal and brake lights of the trailer. This allows other drivers on the road to know when the tow vehicle is turning left.
When the tow vehicle’s brake pedal is pressed, power is also sent through this pin to activate the brake lights of the trailer. This lets other drivers know that the tow vehicle is slowing down or stopping.
To properly wire this pin, connect the left turn signal and brake lights of the trailer to the green wire of the Bargman plug.
Pin 2: Reverse Lights
Pin 2 of the Bargman plug is used for the reverse lights of the trailer. When the tow vehicle is shifted into reverse, power is sent through this pin to activate the reverse lights of the trailer. This allows other drivers to see that the tow vehicle is backing up.
To properly wire this pin, connect the reverse lights of the trailer to the blue wire of the Bargman plug.
Pin 3: Ground
Pin 3 of the Bargman plug is the ground pin. It is used to ground the electrical system of the trailer to the tow vehicle. This ensures that there is a complete circuit and that all electrical functions work properly.
To properly wire this pin, connect the ground wire of the trailer to the white wire of the Bargman plug.
Pin 4: Tail Lights
Pin 4 of the Bargman plug is used for the tail lights of the trailer. When the tow vehicle’s headlights are turned on, power is sent through this pin to activate the tail lights of the trailer. This allows other drivers on the road to see the trailer in low-light conditions.
To properly wire this pin, connect the tail lights of the trailer to the brown wire of the Bargman plug.
Pin 5: Right Turn Signal and Brake
Pin 5 of the Bargman plug is used for the right turn signal and brake lights of the trailer. When the tow vehicle’s right turn signal is activated, power is sent through this pin to the right turn signal and brake lights of the trailer. This allows other drivers on the road to know when the tow vehicle is turning right.
To properly wire this pin, connect the right turn signal and brake lights of the trailer to the yellow wire of the Bargman plug.
Pin 6: Brake Controller Output
Pin 6 of the Bargman plug is used for the output of the brake controller of the tow vehicle. This pin sends power to the trailer’s electric brakes, which are activated when the tow vehicle’s brake pedal is pressed. This allows the tow vehicle to control the braking of the trailer, ensuring safe and reliable towing.
To properly wire this pin, connect the output of the brake controller of the tow vehicle to the blue wire of the Bargman plug.
Pin 7: 12V Power Supply
Pin 7 of the Bargman plug is used for the 12V power supply of the trailer. This pin provides power to the trailer’s interior lights, brakes, and other accessories that require 12V power.
To properly wire this pin, connect the 12V power supply of the trailer to the black wire of the Bargman plug.
FAQs
Q. What happens if my Bargman plug is wired incorrectly?
A. If your Bargman plug is wired incorrectly, you may experience electrical problems when towing your trailer. Some of the symptoms of incorrect wiring include malfunctioning turn signals and brake lights, dim or flickering lights, or no power to the trailer at all. It is essential to properly wire the Bargman plug to ensure safe and reliable towing.
Q. Can I use a 7-way Bargman plug on a 4-way trailer?
A. Yes, you can use a 7-way Bargman plug on a 4-way trailer by using an adapter. The adapter will convert the seven pins of the Bargman plug to the four pins of the 4-way trailer plug. However, keep in mind that you will not have access to all of the electrical functions that a 7-way plug provides.
Q. How do I test my Bargman plug?
A. To test your Bargman plug, you will need a circuit tester. Connect the circuit tester to each pin of the Bargman plug while the tow vehicle’s electrical system is activated. The tester should show a clear and steady signal for each pin. If there is no signal or a weak signal, there may be a problem with the plug’s wiring or the electrical system of the tow vehicle or trailer.
Q. How do I replace a damaged Bargman plug?
A. To replace a damaged Bargman plug, you will need to disconnect the old plug and remove any damaged wiring. Then, connect the new plug according to the wiring diagram, ensuring that each wire is properly connected to the correct pin. Use electrical tape or heat shrink tubing to protect the connections and ensure a secure and reliable connection.
Conclusion
A 7-way Bargman plug wiring diagram is essential for safe and reliable towing of your trailer. By understanding the seven pins and their functions, you can properly wire the Bargman plug to ensure that all electrical functions work properly. If you have any questions or concerns about wiring your Bargman plug, consult a qualified electrician or mechanic.
