Hello. I have a cat f35 5fb1558. Intermittent no hyd. When hyd do not work the dash display shows a zero, when they do work the dash shows a number. only by flipping key switch it changes. Sometime they work sometime they don't. The numbers that do display change also. Is this battery display or something else. Not educated on this system. Hyd work when manually pushing hyd contactor. Battery is 37v. Please help. Thank you.