what is a 7 pin wiring harness
7 pin wiring harness, generally refers to a cable assembly with a 7 pin connector. It is very helpful for trailer harness wiring and is usually used for transmitting data, signals, electricity, etc.
It is widely applied in towing equipment such as trailers, tractors, SUVs, and large trucks. for example, there are 7 pin trailer wiring kit with electric brakes,wiring for trailer hitch, 7 pin trailer wiring connector, and 7 plug wiring harness. In trailer applications, the 7 pin wiring harness mainly serves to connect the trailer with the electrical control system.
The application of 7 pin wiring harness
The 7 pin harness is typically used in trailer systems. Common specific products include the 7 pin trailer wiring kit and the utility trailer wiring kit. We can see 7 pin sockets at the rear of various large trucks or vehicles used for towing and moving heavy objects, and there are 7 pin plugs on vehicles. This is the 7 prong trailer wiring kit.
Vehicle towing application:
1.Station wagon trailer towing equipment
In the trailer towing application of station wagons, the functional usage scenarios of 7 pin trailer harness include:
Electric braking: This is a crucial safety feature. When a vehicle brakes, this function sends a signal to the vehicle's braking system, enabling the vehicle to brake synchronously and preventing vehicle accidents.
Reversing:When reversing with a tow truck, the reversing light at the rear of the vehicle will illuminate, alerting the vehicles and people behind to pay attention to safety.
Auxiliary power supply: It can replenish the power of the station wagon when the battery is low during driving, and also continuously supply power to the electrical equipment inside the vehicle.
Signal lights: This includes transmitting signals such as brake lights and turn signals to external vehicles to ensure the safety of vehicles behind.
2.Cargo trailer towing and commercial equipment
7 wire trailer harness is used in commercial equipment applications, such as trucks for transporting goods, engineering equipment trailers, etc. These applications also require light signals and electric brakes to safely carry the equipment, and also serve as the power source in the trailer equipment, providing power for the ventilation and monitoring facilities of the trailer.
3.Yacht trailer towing equipment
When towing large yachts, due to their large size and certain weight pressure, especially on slippery roads after rainy days, accidents are highly likely to occur. To ensure operational safety, the functions of the seven pin wiring harness need to be used. For example, in the electric braking function, it is very important to control the safe landing of the yacht.
The function of 7 way wiring harness
The seven pins of the 7 pin thread bundle each have their own specific functions.
Generally speaking, the specific functions are summarized as follows:
|
Stitch |
Function |
Explanation |
|
1 |
Stop signal/Turn left |
Control the left stop light and left turn signal of the trailer |
|
2 |
Reversing lights |
It mainly provides power for the reversing lights of the trailer |
|
3 |
Public Grounding |
Ground all the circuits |
|
4 |
Stop light/Right turn |
Control the right stop light and right turn signal of the trailer |
|
5 |
Electric brake |
Send a braking signal to the braking system of the trailer to make the vehicle brake synchronously |
|
6 |
Driving lights/taillights |
Provide power to the license plate lights, taillights and other components of the trailer |
|
7 |
Auxiliary Power Supply |
When the trailer's battery is low, recharge it or supply power to the electrical equipment inside the trailer |
 |
 |
Among manufacturers in different parts of the world, due to the differences in regional standards, there will be wire markings of different colors. However, the function of the seven pin trailer harness pins is standardized. It is accurate to take the function as the standard, not the color of the wire as the standard.
Meanwhile, our ECOcables team offers professional customized wiring harness services and has served over 1,000 enterprises. We are capable of manufacturing wiring harness products that are needed in all industries. With the rich experience of our team, we have completed the standardization of many wiring harness products. The following wiring harness products are recommended for you to read：
Frequently Asked Questions
what size wire for trailer lights?
When choosing the size of the trailer wire, it should be based on the current carried by the wire, the length of the wire, the environment in which it is used and its function. Generally, the American wire gauge AWG is used as the standard. The common industry standard sizes for reference are as follows:
|
Function |
Suggested minimum wire size (AWG) |
Recommended heavy-duty and long trailer size (AWG) |
|
Reversing light |
16 AWG |
14 AWG |
|
Public grounding |
12 AWG or 10 AWG |
10 AWG |
|
Electric brake |
10 AWG |
8 AWG |
|
Turn signals/brake lights |
16 AWG |
14 AWG |
|
Driving lights/taillights |
16 AWG |
14 AWG |
|
Auxiliary power supply |
10 AWG or 8 AWG |
8 AWG |
how to test 7 pin trailer plug?
To test whether the 7 pin trailer plug can be used normally, it is necessary to first ensure that the vehicle is in a safe parking state. Use a professional trailer wiring tester, which is the simplest and fastest tool for users. It can be directly plugged into the 7-pin socket of the trailer, and the screen on the tester will display whether the status of each pin is normal.
When operating, start the tests of each item according to the characteristics of the vehicle. For example, if you need to turn on the ignition switch of the trailer but do not start the engine, then start other items that need to be tested. When turning on the reverse lights, it is generally necessary to shift into reverse gear. However, some vehicles need to start the engine to test the auxiliary power supply.
If the corresponding light on the trailer wiring tester is on, it indicates that the function is normal. If it is not on, it means there is a problem with the circuit of this function.