Wiring systems

Continuing increases in vehicle features mean more circuits and greater functionality need to be integrated into the vehicle’s wiring system.

Also, weight reduction is a continuing requirement and optimised vehicle packaging can potentially result in less space being available for the wiring system. And all this in a development timeframe that continues to get shorter. Our expertise ensures the whole EDS system is optimised throughout the development process – including weight reduction and functional integration where possible.

LEONI responds to these challenges with the right solutions:

  • Optimised wiring system designs for all vehicle types from low cost cars to premium brand vehicles
  • Configurable power distribution modules
  • Use of alternative conductor materials
  • Special components for hybrid / electric vehicles
  • Proven overfoaming technology, producing harnesses that are dimensionally stable, easy to install and which save space
  • Overfoamed connectors and grommets
  • Vehicle EDS system measurement, simulation and validation

Full EDS architecture

Frequently the EDS system architecture needs to reflect the topology and structural design of the vehicle.

There is never just one answer. Optimised EDS system architectures enable us, in most cases, to reduce the weight of a vehicle’s wiring system. Less weight means lower fuel consumption and reduced exhaust emissions – good news for our customers and great news for the environment.

Our expertise, integrated in-house CAD tool chain and understanding of the market trends mean, when developing a vehicle’s full EDS architecture, we can consider the following:

  • EDS network concept
  • Functional partitioning
  • Feature list
  • ECU hardware
  • Grounding concept
  • Power distribution
  • Packaging
  • Harness partitioning
  • Harness routing
  • Wire dimensioning

Engine harnesses

Engine harnesses operate in a very hostile environment, exposed to very high temperatures as well as engine fluids, vibration and salt spray.

Engine harnesses sometimes even run inside the engine. Designing and manufacturing engine harnesses with full protection is a core skill of LEONI. Engine harnesses for all market sectors – light vehicles, trucks and off-highway vehicles.

We always ensure the engine harness is fully protected – this can include custom designed grommets, formers and protector brackets.

Another example of engine harness protection is our innovative overfoaming technology for pre-formed harnesses. This ensures that all wires are fully protected against extreme temperatures, dirt, moisture, vibration and abrasion. Easier fitting in the tightest of spaces is another benefit of this technique.

Pre-formed harnesses

Technical sub harnesses

Vehicle navigation, telematics, high-specification in-vehicle entertainment systems.

These increasingly popular vehicle features often require special connectivity solutions. For example, the high levels of data transfer may involve special shielding to minimise EMI (electro-magnetic interference).

LEONI has the expertise and experience to ensure everything works perfectly. For example – we have been manufacturing POF (plastic optical fibre) in house for over 10 years. Our specially designed facilities assemble MOST harnesses with 100 % optical attenuation testing.

Pre-formed harnesses

A wiring harness is typically a two-dimensional object.

This has to be transformed into a specific, three-dimensional shape using, for example, formers, protector brackets and tape. In contrast a pre-formed wiring harness is produced in a stable, three-dimensional form using specially formulated coating materials. This technique protects the harness against dirt, fluids, extreme temperatures, vibration and physical damage. 

The pre-formed harness enables the harness to be routed around complex shapes e.g. engines, gearboxes and axles. Geometric flexibility is built in to assist product handling and installation.

Key benefits:

  • Integrated mounting and fixing elements, including connectors
  • Exact fit in the vehicle – easy and quick installation on the vehicle assembly line
  • Reduced parts count and product variety
  • Opportunity to increase the level of automation

Overmoulded solutions

Overmoulded electrical and electronic components are fully protected to ensure reliable connections.

Different designs of over-moulded connectors, including customer specific solutions, allow harnesses to be fitted more easily where space is tight. This technique ensures increased protection against the ingress of water, salt, dust and corrosive chemicals. More functions can be integrated into a small harness which is 100 % tamper proof and has easy tamper detection.

Sophisticated CAD tools and proven experience in cable extrusion, plastic injection moulding and product assembly enable us to provide solutions where there are no standard answers. Especially in situations where safety and reliability are critical. Our expertise covers the development of plug-in and screw-in connections, sensor mountings along with other metal and plastic parts used in conjunction with different cable types. Incorporating sensors, actuators, specialist cables, interconnects and other devices in an over-moulded harness assembly delivers high levels of safety and reliability.