[Daryles]

Jay, you are correct, if your converter is working you will have 12v lights, and furnace etc. which is a good thing (converter works).
However the hydraulic system pump may not. It requires high amps (>80A) to run.
You can take the old batteries to any auto parts store and they will test them.

You would think the Level-up control panel would at least light up. Did you check that fuse above the hydraulic motor in the corner?