when you say "no display on the dash" do you mean there is nothing on the dash at all? or just no display you recognize? including the icon strip? is the key switch still working?
On the "main logics board" (EV100 card), there is a terminal board consisting of 2 rows of 3 wire connections each row, held on with screws in between 2 small plugs and 2 larger plugs, are those plugs in all the way, and what voltages do you have on the 6 wires attached with the screws, first with the key switch off, then the key switch on, then someone on the seat with the key on, and off the seat with the key on. in particular, the one on your left in the row on the back, as far as voltage from the key on and off, and the top row all the way to your right (looking at the card from standing at the rear of the truck) as far as someone on the seat.
Also, on this truck what is the ohms (not volts) showing between frame and battery connectors, both sides, with battery disconnected, (must be less than 100K ohms, but that causes weird intermittent failures [A.K.A. "WIF"] not "no display", but a display failure can be one of the WIF caused by short to frame, and you should know that battery forklifts do not have "ground" like an auto, but do have 'negative return to battery' through wires and cables)