How to prevent and screen the failures of automobile terminal-blocks?

In order to ensure the quality and reliability of automobile terminal-blocks and prevent the occurrence of failures, it is recommended to study and formulate corresponding screening technical requirements according to the technical conditions of products, and conduct the following targeted reliability tests.
1. Prevent poor exposure
1) Guide detection
The ordinary automobile terminal-block manufacturers do not have this product acceptance test, and users generally need to conduct guide detections after installation. Therefore, it is suggested that 100% point-to-point guide tests should be added by manufacturers for some key models of products.
2) Instantaneous detection
Some connecting terminals are used in dynamic vibration environments. The test shows that the reliability of contact points in a dynamic environment cannot be guaranteed solely by checking whether the static contact resistance is qualified.

Because connectors with contact resistance still frequently power off during simulated environmental tests such as vibration, impact, etc., thus, for some terminal blocks that require high reliability, it is best to conduct 100% dynamic vibration test to assess their contact reliability.
3) Single-hole separation force detection

The single-channel separation force refers to the separation force of the inserted contact from static to moving, which is used to characterize the contact between plug and jack. The test shows that the separation force of single hole is too small, and there is the possibility of impact load under vibration. To test the contact reliability, it is more effective to measure single-hole separation force than that of measuring contact resistance. It is found that the contact resistance measurement of the jack with poor single-hole separation force is often still qualified. For this purpose, in addition to developing stable and reliable contacts with a new generation of flexible plug-in contacts, manufacturers should not use automatic plug-in force tester for multi-point simultaneous measurement on key models, and 100% of the finished products should be checked point by point to prevent signal instantaneous disconnection of individual key models.
2. Prevent poor insulation
1) Insulation material examining

Whether the quality of the raw material is good has a great impact on the insulation performance of the insulator. Therefore, the selection of raw materials is particularly important. We should not blindly reduce the cost at the expense of losing the material quality. Instead, we should choose reputable large factory raw materials. For each batch of incoming materials, carefully check the inspection batch number, material certificate and other important information. Do a good job in the traceability data of material use. 
2) Insulation resistance test of insulator

By 2012, according to process regulations for some production plants, electrical performance tests shall be performed after assembly. It turned out that all insulators can only be scrapped because their insulation resistance is unqualified. The reasonable process should be 100% process screening of insulator components to ensure qualified electrical performance.
3. Reduce discomfort
1) Interchangeable test

The exchange test is a dynamic test. It is found that paired plugs and sockets in the same series can be inserted to each other, so as to find out whether they cannot be inserted, positioned and locked due to excessive size of insulation, contact parts and other parts, or improper assembly, even causing disintegration under the action of rotating force. Another function of interchangeability test is to timely find out whether there is metal surplus through plug-in connection such as thread and bayonet, to check if affect insulation performance. Therefore, 100% inspection shall be carried out for some important purposes on automobile terminal blocks to avoid such serious and fatal failure accidents. 
2) Torque resistance test

Torque resistance test is a very effective test method to test the structural reliability of automobile terminal blocks. According to the requirements of US military standard MIL-L -39012, samples shall be taken from each batch according to the standard for durability torque inspection to find problems in time.
3) Comprehensive measurement of the voltage wiring

During electrical installation, it is often found that individual core pressure wiring is not placed well, or locked after placing, and the contact is unreliable. For individual mounting hole, the screw teeth are stuck due to burr or dirt. Especially when the factory electricity is installed into the last few mounting holes of a plug base, after such defects are found, the other installed hole-press connecting wire have to be removed one by one and replaced again. In addition, the selection of wire diameter and compression aperture is not reasonable, or due to the wrong operation of the pressing process, which may also lead to poor head pressure. Therefore, before the finished products leave the factory, the manufacturer shall conduct a fully test on all mounting holes for delivered plug (base) samples, that is, use the unloading tool to position the plug or pin wire and check whether they are locked. According to the requirements of product specifications, the tensile force detection of each pressure wiring shall be made.