Acting strange

:o) The JPX300H doesn't have a "motherboard", but maybe a timing module. Either way, even if the machine only runs one cycle, it suggests the timing board is working correctly. You have multiple problems. For starters, the leak is probably a loose hose clamp, most are located on the unside of the machine. The most difficult are the drain lines which are to the rear.
The auto/manual switch is pretty straight-forward, but it is a two-part assy; the button, and the switch itself. Check switch for continuity.

sorry, thought it was on there, model number jpx-300h

what model (44??) you need to check the switches on the floats some fill with water but need the model to help you more