About SMMT

Towing Vehicle and Trailer Electrical Connectivity TF

During 2007 the Heavy Commercial Vehicle Technical Committee responded to the UK automotive industry’s need for a solution to the ever present issue of Truck and Trailer electrical connection compatibility, that causes functional and safety problems.

These problems have been exacerbated in recent years with the introduction of LEDs in lamp design due to the legal requirement for activating a cab tell tale when direction indicators on the trailer fail. Sensing of this failure in “LED” lamps is difficult and needs a harmonised technical solution for industry adoption.

The SMMT “Towing Vehicle & Trailer Electrical Connectivity” Task Force has been set up to develop suitable solutions to the aforementioned problems, and commenced activities on 28th November 2007. Membership comprises representatives from the UK Heavy Truck, Trailer, Lamp and Electronics industry sectors. Due to the global nature of companies in these sectors many UK manufacturers are part of mainland Europe corporations requiring the Task Force to include expert guests from Germany and Sweden etc. In addition, output from a previous German industry informal working group has been input to the task force with an ongoing link via the guest members.

Main objectives of the task force are:-

• Develop industry harmonisation protocol for towing vehicle/trailer connector utilisation and signal transmission in the combination.
• Include a suitable “LED” direction indicator failure signal technical specification in the protocol.
• Convert industry protocol to a new ISO standard.
• Liaise with the mechanical coupling industry sector to monitor development of an all new design concept for towing vehicle/trailer coupling, providing input for electrical connectivity and signal transmission in the combination.
• Create new industry standards for the electrical connectivity and signal transmission in the combination.
• Co-develop new ISO standard to support introduction of the all new combination coupling design, including electrical connectivity and signal transmission.
• Update UNECE regulations to support type approval, referencing the new ISO standards for next generation of towing vehicles and trailers.

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