The Diversity of Automotive Connectors

There’s now a bewildering array of automotive connectors. At one extreme high-current power connectors, at the other fibre optic data connectors. This article describes some of the different applications of automotive connectors, highlighting some illustrative products.


Automotive Powertrain

The powertrain subsystem is responsible for generating power and delivering it to the road. Electronics in the powertrain includes the engine control unit (ECU) and transmission control unit, often combined into one module. These electronic modules experience the harshest environmental conditions of any of the electronics in the car since they are located in the engine compartment.  Connectors in this application must withstand the extremes of temperature, plus severe vibration, as well as the presence of moisture, oil and other potential contaminants.

High reliability connectors with the best temperature and vibration performance are therefore required, and they should be sealed to keep out contaminants that may be present in the engine compartment.

Figure 1: Molex CMX Series connectors are sealed to IP6k9k
and are widely used in engine control units


Molex has worked with automotive OEMs since the end of the 1990s to define a standard interface with the engine control unit, resulting in development of the CMC range of connectors. CMC is a wire-to-board, IP6k9k-sealed, hybrid, modular family with between 32 and 53 connections. These connectors are widely used in engine control units, automatic gearboxes and suspension controllers today. A newer version, the CMX series, offers a more sophisticated design for the interfacial seal, which ensures that the connector remains protected before mating, and during mating and unmating.


Safety Connectors

Automotive safety systems such as airbags and anti-lock brakes, and ADAS systems like radar, depend on input from sensors around the vehicle to gather data about the environment the car is in. Connecting to these sensors is therefore vitally important if the car is to receive enough data to act on it in the right way. Since actions taken by systems such as ADAS can control systems like the brakes, safety is paramount. Reliability and durability of the connectors used to connect to sensors has a direct contribution to the reliability of the car’s electronic systems and, therefore, the safety of its occupants.

Trends for sensor connectors in vehicles include their overall decreasing size and the predominance of solderless, compliant-pin designs. Molex’s ideas for the next generation of sensor interconnects therefore include a 0.5mm mating terminal that reduces the size of 0.64mm compliant-pin PCB terminals.


Body Electronics

Electronics in the body of the car are still required to withstand the extremes of vibration and temperature, but conditions are not as harsh as inside the engine compartment. The car body houses a lot of wiring, for example, inside the door to raise and lower the windows, or activate motors that move the mirrors. Given the automotive industry’s drive to pack more and more electronics into smaller spaces, connectors in these systems are therefore required to be small and lightweight, not forgetting waterproof.

Ideal for body electronics, the Mizu-P25 wire-to-wire connector system is small and light, so that wires with connectors fitted may be passed through small holes or hinges during vehicle assembly. This series has IP67 protection and comes in 125-V or 250-V rated versions.

Figure 2: Molex’ Mizu-P25 series is small enough to
fit through tight holes in door assemblies


Passenger Comfort and Infotainment

Interior lighting, navigation systems and entertainment modules are responsible for a large proportion of the electronics in a modern vehicle. While they are perhaps not subject to the harshest of environments (except perhaps shock and vibration), functionality of these systems is essential to the marketing of new models of vehicle, and the technology moves fast to keep up with consumer expectation. 

Figure 3: The Stac64 stackable connection system supports both
signal and power connections, boosting design flexibility


The Stac64 stackable connection system suits vehicle interior electronics and infotainment systems since several connectors may be joined together to support more than one module. Stac64 is for both low-level signals as well as power up to 30A, helping design flexibility, and eliminating the need for custom tooling. It meets USCAR-2 Class II mechanical and electrical performance characteristics for unsealed connector applications.


Vehicle Networking

As vehicles become increasingly electronic, in-vehicle networks gain importance. Whether it’s a MOST network used to communicate safety-critical camera data in real-time for an ADAS system, or USB streaming the movies the kids are watching in the back, there are often many different types of network in the same vehicle. Demands on data connectors are therefore diverse, but all require support for a certain level of signal integrity and speed.

Figure 4: HS AutoLink Connectors are a ruggedised version of
a popular consumer data connection system

Molex has ruggedised a popular five-pin shielded connector system from the consumer market for vehicle networks. The HSAutoLink data bus system incorporates USB, LVDS, FlexRay, MOST and Ethernet connectors, all optimised for high-speed communication to ensure vehicle networks perform to the highest possible standard.

Molex automotive connectors available from RS Components may be viewed here.