Voltbike Yukon battery tests good but no power.

Im new here and have a voltbike 750 yukon with the 10 amp hour battery i bought used this past spring. The bike was great til it stopped running two weeks ago. Went for a ride washed it down as usual. Next time go to ride no power black screen. Battery seemed to take a charge, took it to an electrical shop tested just fine. Voltbike thought maybe a bad connection so i bought a new ignition and wires but no difference. today took out controller all lines seem to be good nothing seems burnt. Grey/red wire and brown/red wire from controller not hooked to anything. Single brown wire from other side not hooked to anything. Anyone have any ideas?
Have you fixed the black screen issue. Sounds like water got either into the control buttons or the screen. Did you replace either?
i think the screen is black because no power is coming thru, i have a second display and controller button, made no difference