Automotive connector standards

Automotive-grade electrical connectors: invisible but critical to the operation of the car.


Considering our responsibility for our safety and general well-being, all-electric car components must be able to withstand frost, heat, and uneven terrain. Not surprisingly, the electronics that make up every vehicle today require extensive testing, including checking of connectors and cables that writhe invisibly in modern vehicles.

Maintaining high-quality car components

All car manufacturers create their models by collecting parts from many different suppliers and assembling them into a finished product. On the one hand, manufacturers are technically dependent on suppliers, but on the other hand, they enjoy a very strong position in the market. This advantage allows companies such as Toyota to impose stringent quality standards on their suppliers.

To learn more about the general requirements for automotive-approved connectors, a good starting point is a USCAR2-7 specification, developed by the Society of Automotive Engineers (SAE) and the United States Council for Automotive Research. ). This nearly 80-page document contains extensive and precise information about the tests that must be carried out on connectors used in cars.

The tests mentioned in this document include:

  • Systematic, mechanical loading of the connector
  • Vibration tests
  • Submitting components in car fluids and even saltwater
  • Thermal cycles. The connector may perform as expected at room temperature, but these tests evaluate whether the device will also function in extreme temperatures.
  • Electrical resistance. To pass this test, the connector must have a resistance of 500MOhm between the sections of the connector when a voltage of 500 VDC is applied.

Of course, even a long and detailed document such as USCAR2-7 cannot predict every situation. The document itself emphasizes that many cases require a different test suite, which may be more or less stringent than the base specification prescribes. In such circumstances, the so-called 'Authorized person', whose duty is to register any changes to the standard procedure. Manufacturers can then refer to this information before deciding to accept components.

It is important to be aware of the full context of a specific joint application - this ensures that each part will be properly tested. To this end, component manufacturers define classes for the following variables:

  • Temperature resistance (T1-T5)
  • Tightness (S1-S3)
  • Vibration resistance (V1-V5)

The high-rated component will have to undergo much more extensive testing than the lower-ranked component. Lower ratings are for components used in the car's passenger compartments where, for example, excessive humidity is not a problem. Components with higher ratings are used in the engine compartment and the like where extreme temperatures and humidity will occur. Vibration ratings range from a similar V1 specification for light-duty, all the way to Class V5 automotive connectors. Rating V5 may apply to unsprung components attached directly to the car's wheel, which are exposed to constant vibrations that must be almost completely eliminated by appropriate fastening. These tests are designed to ensure that automotive components will generally withstand 200,000 miles of heavy use and will encompass millions of impacts, vibrations, and temperature variations.

Automotive standards in electronic components

Tests can help ensure that your car components are of the highest quality, but what are the consequences if a part fails? If the connector comes loose on the radio system or DC power socket, the driver will likely be annoyed, but nothing else. If, however, there is a failure of the airbag deployment system, the consequences can be much more severe; an airbag may not deploy, inflate correctly, or at the wrong time. These dangerous incidents are quite rare, however, even a single failure or error that leads to a tragedy can permanently damage the car manufacturer's reputation. To protect their customers and their own performance, manufacturers systematically assess the risks of their vehicles.

The International Organization for Standardization (ISO) presented the risk assessment process, and the specific requirements for motor vehicles are included in the ISO 26262 standard. Its discussion is far beyond the scope of the article, but for both component manufacturers and cars, it is probably an absolutely basic document.

When dealing with a device described as an 'automotive connector' or the term 'automotive grade', you need to know that winning these titles meant passing a series of tests and meeting rigorous standards. Automotive suppliers have adequate resources to be able to check that each component meets SAE and ISO standards, which probably also includes additional plant inspections and other requirements defined by the aforementioned 'authorized person'. Consumers have neither these resources nor in-depth market knowledge, so when purchasing connectors on your own it is extremely important to buy from a trusted source.

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