Abstract: A method and apparatus for permitting use of an ABS electrical power circuit associated with a tractor-trailer vehicle to provide auxiliary power whenever the trailer is parked and which provides for full power to an ABS brake control circuit through the ABS electrical power circuit in response to air pressure in the emergency brake supply line of the tractor-trailer vehicle being above a predetermined minimum which is sufficient to release the trailer's emergency brake and permit movement of the trailer.

Abstract: Control valve assemblies for regulating the parking/emergency spring brakes of a tractor trailer air brake system which include valve components for insuring that the spring brakes are not released until pressurization of the system's service reservoir is achieved and which components are operable to exhaust the spring brakes to atmosphere upon the failure of the supply pressures within the system to thereby automatically apply the spring brakes. In one embodiment, the valve components permit pressure to be supplied to release the spring brakes under circumstances when it is not possible to pressurize the service reservoir.

Abstract: A female connector plug especially for tractor-trailer interconnection has a plurality of wires permanently connected to split terminals having spring ring retainers and with shrink tubing casings encapsulated within a resilient elastomeric body which may have a pistol grip configuration.

Abstract: An air brake control system for use in truck trailers, including tandem trailers, having at each axle compressed-air spring brakes and service brakes with each trailer being coupled to receive compressed air through an emergency (supply) gladhand and to receive service brake signals through a service (control) gladhand and which includes an integrated brake valve system for each trailer within a common valve housing.