30more, if you donít have schematics for your 1998 Pinnacle you may have to trace out things and make your own schematics. I donít know what kind of battery control system your 1998 coach uses but I would first check that the alternator is charging both chassis and coach batteries correctly. More modern RVís use various battery control systems (BIRD, BIM, BCC) to monitor battery string voltages and allow the connection of the coach and chassis batteries together under various charging and emergency starting scenarios. I donít know if your coach uses any of these systems.
I would ďguessĒ that your hydraulic motors are powered off coach batteries (which is typical for newer coaches), and if they are in good state of charge and receiving charge from the alternator you should have lots of juice. So the question is what breakers or fuses are in line between the coach batteries and your hydraulic motor(s). On my coach there is a 100 amp resettable breaker. So I would start tracing/investigating the actual circuit that powers your hydraulics. Use a voltmeter and trace out along the hydraulic circuit to where your coach battery DC voltage stops.