Semi-trailer use experience - circuit

The semi-trailer circuit is not complicated, but many users often encounter some circuit faults or problems during the use of the vehicle. Today, the editor will share with you the precautions for the use and maintenance of the trailer circuit and the knowledge of typical fault troubleshooting.

The semi-trailer is to connect the spiral cable plug of the tractor to the circuit socket at the front of the trailer to transmit the light signal of the main vehicle to the trailer. Therefore, the vehicle is equipped with an internationally universal electrical system that matches the tractor. The electrical system is generally composed of seven-core sockets, multi-core cables, junction boxes, waterproof connectors, and various lamps and other components. The front crossbeam of the semi-trailer frame is equipped with an electrical connection socket, and the rear of the frame is equipped with brake lights, turn signals, rear position lights, reversing lights, license plate lights, and fog lights. The front and both sides of the frame are equipped with front position lights, side turn (side position) lights, side marker lights, and side reflectors. The voltage of various lamps is DC 24V or 12V. In recent years, many vehicles have also begun to use integral wiring harness circuits, which are more waterproof and reliable.

After the customer hooks up the new vehicle, the seven-core plug and handshake of the main vehicle electrical circuit need to be connected to the trailer, and the trailer light signal needs to be tested. When our trailer is offline, the electrical system has been tested in accordance with national standards using an electrical test bench, and generally there will be no problems. But sometimes because the customer’s front is a new car, the following problems may occur: 1. The lights of the main trailer are inconsistent; 2. There is no signal for some lights; 3. The fuse of the main vehicle is burned. When these problems occur, it is recommended to use a multimeter or a test light to check whether the seven-core plug of the main vehicle is powered?

If the seven-core plug is wired correctly, there will be no problem with the light signal of the trailer, otherwise the seven-core socket needs to be disassembled and the relevant wire ends need to be adjusted. If you find the above problems when picking up the car from our company, you can ask the service staff of the dispatch center to help you solve them. If you find them in other places, you can contact the local main vehicle service station for adjustment.

After the vehicle has been used for a period of time, the electrical system is prone to short circuits and open circuits. Please pay more attention when checking: Is there any friction damage where the line is not fixed? Is the connector loose or flooded? Are the wire fixing screws of the seven-core plug and seven-core socket loose? Generally speaking, most of the problems can be solved by checking the above parts. Attached below is the circuit diagram of our vehicle, which marks the wire colors of various lamps and the locations where they are connected to the seven-core socket, which is more convenient.