Power and communications link between a tractor and trailer

A method of operating an electronic tractor control module to provide a dedicated electrical power line from a tractor electrical system to a trailer, the method comprising the steps of:

• controlling a first switching device, associated with the tractor control module and having an output connected to the trailer, to establish a single unpowered communication line therethrough from the tractor control module to the trailer by disconnecting a first electrical line of a trailer electrical system from an input thereof and connecting a communication port of the tractor control module thereto;
• monitoring the single unpowered communication line for a heartbeat signal;
• controlling a second switching device, associated with the tractor control module and having an output connected to the trailer, to provide a dedicated power line from the tractor electrical system to the trailer if the heartbeat signal is detected on the single unpowered communication line within a first predetermined time period after establishing the communication line by disconnecting a second electrical line of the tractor electrical system from an input thereof and connecting an electrical power line of the tractor electrical system thereto;
• and
• controlling the first switching device by disconnecting the communication port from the first switching device input and connecting the first tractor electrical system electrical line thereto if the heartbeat signal is not detected on the single unpowered communication line within the first predetermined time period after establishing the communication line.

A method of operating an electronic trailer control module to provide a dedicated electrical power line from a tractor to a trailer electrical system, the method comprising the steps of:

• controlling a first switching device, associated with the trailer control module and having an output connected to the tractor, to establish a single unpowered communication line therethrough from the tractor to the trailer control module by disconnecting a first electrical line of a trailer lighting system from an input thereof and connecting a communication port of the trailer control module thereto;
• sending a heartbeat signal on the single unpowered communication line;
• monitoring the single unpowered communication line after sending the heartbeat signal thereon;
• controlling a second switching device, associated with the trailer control module and having an output connected to the tractor, to provide a dedicated power line from the tractor to a trailer electrical system if an acknowledgment signal is detected on the single unpowered communication line within a first predetermined time period after sending the heartbeat signal thereon by disconnecting a second electrical line of the tractor lighting system from an input thereof and connecting an electrical power line of the trailer electrical system thereto.

Power and communications link between a tractor and trailer comprising:

• means associated with the tractor for switching a plurality of electrical lines extending into the trailer between an electrical line forming part of an electrical system of the tractor and one of an electrical power line and a first unpowered communication line;
• means for controlling said means associated with the tractor for switching a plurality of electrical lines extending into the trailer and for sending and receiving communication signals on said first unpowered communication line;
• means associated with the trailer for switching said plurality of electrical lines extending into the trailer between an electrical line forming part of an electrical lighting system of the trailer and one of an electrical line forming part of a trailer electrical system and a second unpowered communication line;
• and
• means for controlling said means associated with the trailer for switching said plurality of electrical lines extending into the trailer and for sending and receiving communications signals on said second unpowered communication line;
• the power and communications link operable to connect said first communication line to said second communication line to form a single unpowered communication line between the tractor and trailer, and to route electrical power from the electrical system of the tractor to said trailer electrical system.

Power and communications link between a tractor and trailer comprising:

• a first plurality of switching devices each having an input switchable between an electrical line forming part of an electrical system of the tractor and one of a tractor electrical power line and a tractor electrical ground line, and an output;
• a tractor control module associated with the tractor for controlling said first plurality of switching devices, said tractor control module having a communications port;
• a second plurality of switching devices each having an input and an output switchable between an electrical line forming part of a trailer lighting system and an electrical line forming part of a trailer electrical system;
• a trailer control module associated with the trailer for controlling said second plurality of switching devices, said trailer control module having a communications port;
• means for connecting said outputs of said first plurality of switching devices to said inputs of said second plurality of switching devices;
• and
• a single unpowered communications line connected between said tractor control module communications port and said trailer control module communications port, said tractor and trailer control modules operable to communicate via said single unpowered communication line.