As an important branch of the RV, the trailer car is the absolute mainstream in Europe, America and other countries. At this stage, RVs in my country are still a niche product for the time being, and trailer-type RVs are even more niche among the niches. Not to mention using them, even if there are very few people who really understand them. Many people think that a trailer can travel as long as it is towed by a trolley, but obviously it is not that simple. The charging, lighting, and braking of the trailer all need to be connected with the towing vehicle, so how to connect? Today we will talk about this issue and give you a reference.
The trailer harness is divided into two parts. The interface on the tractor is called the female connector, and the harness interface on the RV or trailer is called the male connector. Common trailer harnesses are divided into 4-pin, 7-pin and 13-pin types. Among them, the 4-pin harness interface is a motorcycle trailer interface. The male harness only has four wires: left turn signal, right turn signal, tail light, and ground wire, while the female harness has brakes, left turn signal, right turn signal, tail light, Five ground wires are connected. The 4-pin wiring harness is mainly prepared for motorcycle trailers and has little to do with RVs, so I won’t give a detailed explanation here.
The 7-pin wiring harness and the 13-pin wiring harness are specially prepared for towing RVs. The installation of the 13-pin wiring harness is easier than the 7-pin wiring harness, so let’s talk about the connection method of the 13-pin wiring harness first.
The 13-pin wiring harness is also called the European wiring harness interface because it is commonly used in European trailers. my country’s requirements for vehicle lighting are similar to those in Europe, so we feel more convenient when using 13-pin wiring harness. The interface of the 13-pin wiring harness includes brake lights, left and right turn signals, running lights, reversing lights, fog lights, long fire wires, ground wires, etc. It is worth noting that although there are brake lights in the wiring harness, there is no brake. Most European trailers use impact brakes, so there is no need to connect brake lines.
Many European imported vehicles (such as: Volkswagen Magotan Business Travel Edition) will have this 13-pin female wiring harness. Although some vehicles do not have a 13-pin wiring harness female, they have reserved interfaces. Like the “Land Rover Discovery 4” is in the left taillight. When you have the original 13-pin female header, you can use it directly. It is also easier to have reserved interfaces like Land Rover Discovery 4, and there will be optional accessories from the original factory that can be installed.
However, more vehicles do not have these interfaces, and additional wiring is required. Generally, the scheme of routing wires from the rear taillights is adopted. In this scheme, attention should be paid to the bearing capacity of the original car wires and the safety of construction. If the original car has a female 7-pin harness, you can also consider using a harness converter to convert the 7-pin to a 13-pin harness.
7-pin wiring harness, also known as American trailer wiring harness, these 7 wiring harnesses are brake lights, running lights, left and right steering, long live wires, ground wires and spare wires. Pickup trucks such as Raptor F150 and Tundra all have original 7-pin wiring harness females, but please note that the original wiring harnesses of these cars may not match the wiring harnesses of RVs. The original car like the Raptor F150 does not distinguish between the brake light and the turn signal signal, and the brake signal needs to be connected according to the actual situation. The dealer of the RV will provide the drawing of the wiring harness for the specific connection method, and it can be debugged according to the drawing.
Another important point is that the braking mechanism of American trailers is different from that of European trailers. Most of them use electric conduction drum brakes. Without ABS, the brakes lock up easily at low speeds. At this time, another piece of equipment needs to be installed-the brake controller.
The installation and use of the brake controller are very simple, with four positive and negative wires, brake signal input, and brake signal output. There are two solutions for American vehicles that do not have a separate brake signal. 1. Use a decoder to reduce the brake signal and separate it from the original signal. 2. There will be a separate brake signal source at the position of the pedal, from which the separate signal of the brake is drawn. This separate brake signal is then introduced into the brake controller. It should be noted that there is a gyroscope inside the brake controller, so the brake controller needs to be fixed horizontally in the car. When in use, the low-speed brake sensitivity is lowered, and the high-speed brake sensitivity can be adjusted appropriately.
Summary: RVs are not used very much on a daily basis, and most of them are used outdoors, so check the lights and brakes of your RV every time you hook up your tow vehicle to your RV. Don’t panic when there is a problem, most of it is just a bad contact, just pinch it with pliers and it will be fixed. The seemingly simple trailer wiring harness installation is not simple in actual operation. Therefore, it is not recommended to install the trailer wiring harness and brake controller by yourself. It is best to find an experienced car modification shop to do it. After all, sharpening a knife does not cut and dismantle by mistake, and safety comes first.
