Common Fault Conditions Of Automobile Terminal Blocks

The electrical conductivity of plastic insulating materials and automotive wiring terminals are key factors affecting the quality of automotive wiring terminals. They respectively determine the insulation and electrical conductivity of automotive wiring terminals. The failure of any connection end will cause the failure of the entire system engineering. Needless to say, there are many warning cases, and there are various examples here. As a precision work accessory, the quality of the motion control terminal has always been a concern of users. How to effectively detect and prevent it has become a topic of concern to people.

Common failures of automobile wiring terminals.

From the point of view of use, the function that the car terminal should achieve is: the contact should be conductive, the contact must be energized, and the contact must be reliable. The insulation should not lead to the insulation, and the insulation must be reliable. There are three common fatal faults in line terminals:

1. Poor exposure.

The metal conductor in the terminal is a core component, which transmits the voltage, current or signal from the external wire or cable to the corresponding contact, which is the connector. Therefore, the contact must have an excellent structure, stable and reliable contact retention and good conductivity. Contactor structure design is unreasonable, material selection is improper, mold stability is poor, processing size is out of tolerance, surface roughness, heat treatment plating and other surface treatment processes are unreasonable, storage and use environment is bad, and improper operation will cause contact parts and matching parts. Poor contact.

2. Poor thermal insulation performance.

The function of the insulator is to keep the contact in the correct position, and to insulate the contact and the contact, and the contact and the shell from each other. Therefore, the insulating parts must have good electrical, mechanical and process forming properties. Especially due to the large density and the wide application of small size terminals, the effective wall thickness of the insulator is getting thinner and thinner. More stringent requirements are put forward for insulating materials, injection mold accuracy, and molding process. Due to the metal excess, surface dust, flux and other pollution on the surface or inside of the insulator, the precipitation of organic matter and the fusion of the adsorption film of harmful gases and the surface water film form ion conduction channels, moisture absorption, mildew, aging of insulating materials, etc. It may cause poor insulation such as short circuit, leakage, breakdown, and low insulation resistance.

3. The problem of non-retention.

Insulating materials not only provide insulation, but also provide accurate centering and protection for the protruding contacts, as well as the functions of installation and positioning and locking devices. If the installation is not good, it will affect the contacts and cause instantaneous power failure, and the serious thing is the disintegration of the product. Disassembly refers to the unreliable structure of the connecting end due to material, design, process and other reasons in the plug-in state. The abnormal separation between the plug and the jack will seriously affect the power transmission of the control system and the interruption of signal control. Poor installation due to unreliable design, improper material selection, improper selection of molding process, poor quality of heat treatment, mold, assembly, welding, etc., and improper assembly.

In addition, poor appearance due to coating peeling, corrosion, collision, plastic shell flashing, fracture, rough processing of contact parts, deformation, etc., positioning and locking fit size is out of tolerance, processing quality is poor, and the total separation force is too large, etc. Causes of poor shaping. These faults can generally be found and eliminated in time during inspection and use.

How to check the terminal short circuit fault.

The failure of the lead wire and the terminal may also be caused by a short circuit between the wiring harness and the vehicle body (ground wire) or in the related switch. You should first check whether the car wiring terminal is firm, and then perform the test according to the following steps.

1. Check the connection of the wires.

First disassemble the control computer ECU and the control terminals on both sides of the sensor, and then measure the resistance between the corresponding terminals of the terminals. If the resistance value does not exceed 1 ohm, the power cord is normal for the next inspection. When testing the resistance of the lead, it is best to gently shake the lead in the vertical and horizontal directions to improve the measurement accuracy. Multiple wire terminals. The multimeter meter rod should be inserted from the back of the connector, but the waterproof car terminal meter rod cannot be inserted from the back, because the terminal will be deformed if it is inserted slightly accidentally.

2. Detect the short-circuit resistance value.

First, disassemble the wiring terminals on both sides of the ECU of the control computer and the sensor, and then measure the resistance between the terminals of the connectors on both sides and the body. In the measurement, one end of the meter rod is placed on the iron body, and the other end should be measured on the two wire connectors. If the resistance value is greater than 1 ohm, it indicates that there is no short circuit fault.

3. Inspection of terminal appearance and contact pressure.

First disassemble each terminal one by one, and check whether there is rust and dirt on the connector car terminal. Then check whether the junction box is loose or damaged, whether the junction box is firm, and the junction box is not loose after lightly pulling it. Conversely, if it is easier to pull out the plug end of which socket hole, then during use, this socket hole may cause a fault with poor contact.