if the left rear is mounted so that it is facing forward when retracted, it is mounted wrong. that needs to be changed.
the only way any kick down jack will FALL down and contact the road, is for the springs to break, AND the jack to not be fully retracted. if the jack has been correctly retracted, even when dropped down, the foot is about 4 inches above the surface. the park brake has to be set for the pump to operate and extend the jack, so it would take some unusual circumstance for this to happen.
as always, fluid level will not affect hwh jack retraction. this is done with springs, and the light is turned on and off with a magnetic switch, or on older kick down models, a mercury switch.
the jack down light on the older jacks may be a mercury switch located on the back side of the jack. to check this switch just jumper the harness connection with a wire to close the circuit. the light should go off. if it does, replace the switch. the 100/110 service manual shows how to do the diagnosis.
