A light emitting diode lamp includes a lamp body, a current control circuit, and an LED array disposed inside the lamp body. The pass gate is connected to pass through a version of a logic state present at a first input node to an output node when so controlled. At the end of a retraction stroke, a retraction spill passageway that extends through the piston becomes aligned with the retraction spill port and fluid is communicated from the pressurized side of the piston to the unpressurized side of the piston to stop the retraction stroke before the piston \u201cbottoms out\u201d. The estimate is determined consideringa desired future level,actual loading conditions of the vehicle andan actual pressure level of the air container.