well the numbers (?specs?)you quote are only partially correct, as I don't know where your meter is getting it's neg., (unlike a car, electric forklifts should have no frame ground) nor do I know where you are checking to get what you call "input voltage".
when I say "card position one" I am referring to the terminal strip on the ev100 logics card (2 rows of wires connected by screws, the rest of the wires are connected in plugs). left and right are arbitrary as this card (and the whole "chopper panel") can be mounted facing different directions, and what is front or back of a forklift can be confusing to some folks.
If you do not see voltage greater than 3.25 vdc when you have the neg lead of your meter in battery neg (right at the battery) and the positive lead at position 6 of the logics card term board, with key switch on and accel pedal in the "at rest" all the way up, no one touching it, you have some problem related to that pot.