If the pump only activates ; in the retract position ; on the one jack then there is a problem in the control box, that may be only an adjustment for clearance between the lever and the pump activation switch. There may have even been something dropped into the box that's messing things up.
Do you have any info on the levelers manufacturer ? HWH ? Or a model number?
99DSDP 3884, Freightliner, XC, CAT 3126B, 300 HP /ALLISON 3060
2000 Caravan toad, Remco & Blue Ox.