The seal is a very important part of the automotive wiring harness, and its quality is directly related to the function of the wiring harness, whether it is directly used in the wire harness or the automotive connector.

More and more attention has been paid to the durability and reliability of auto parts. As a protective material, silicone rubber parts are widely used in automobiles, among which the importance of the sealing ring is self-evident, especially for the wiring harness protection of the engine compartment and the lower chassis of the automobile, because usually, these two places are more likely to be in harsh environment.

There is a concept of “wet zone” that we need to know. Generally speaking, we refer to the areas where the engine compartment and the lower body of the car are exposed to the air and often affected by rain and water as “wet zone”. Correspondingly, parts like the cockpit and trunk are unaffected by rain and this part is called the “dry zone”.

One of the biggest roles of the wiring harness seal is to isolate the wet area and the dry area. The common part is to assemble one between the engine room and the cockpit to separate the dry area and the wet area. There is also the need to assemble a seal in the left and right rear wheel ABS wiring harness, specifically under the rear seat (such as golf), there is a seal to separate the inside and outside parts, to ensure that the water at the bottom of the driving process will not leak into the cab.

Each qualified wire harness will be tested by a gas seal to ensure that the seal on the automotive wiring harness can work.

What are the principles of testing the quality of automotive seals? The process is simple. That is placing the automotive seal on the mold, and the equipment provides a continuously increasing pressure value, and the air inside is extracted. Within a certain time and pressure value, if the automotive seal can withstand the process, which means it contains good quality, otherwise it is a quality-problem seal.

automotive silicone seal

The electrical appliance in the dry area is less affected by high temperature/humidity and chemicals/dust, while in the wet area, on the contrary, if the seal is poor, it may lead to the water inlet of electrical appliances and wiring harnesses, resulting in short circuit/corrosion of internal circuits, which directly leads to functional failure. Therefore, the connector of wiring harnesses should be sealed. For example, The ESP-SG plug in the engine compartment of an automobile is designed for air tightness. When you open the connector, you can see one layer of the seal with oil. The performance of the seal is directly related to the normal function.

Typically, there are two ways that connectors and other electronic components may get into the water,

  • The external liquid by gravity penetration into its interior, such as connector without seal;
  • Water from the wiring harness internal connection;

Here we should emphasize the word “siphon”, because general electrical appliances will work under a certain temperature, and the inner air will form pressure. When stop working, the temperature and the internal pressure drop then will form a pressure difference, if the connector seal is bad, water vapor will follow the gap between the copper wire into the interior, resulting in function failure; Therefore, connectors in wet areas are generally required to equip well-performed seals.

Typically, there are two ways that connectors and other electronic components may get into the water,

  • The external liquid by gravity penetration into its interior, such as connector without seal;
  • Water from the wiring harness internal connection;
silicone seal manufacturing

Here we should emphasize the word “siphon”, because general electrical appliances will work under a certain temperature, and the inner air will form pressure. When stop working, the temperature and the internal pressure drop then will form a pressure difference, if the connector seal is bad, water vapor will follow the gap between the copper wire into the interior, resulting in function failure; Therefore, connectors in wet areas are generally required to equip well-performed seals.