Way2Roll is correct. It sounds like you have a “power” problem not a “manifold” problem. You need to get a volt/amp meter and start at the battery, and proceed to both the input and output side of the panel, and continue through all the control valves, switches, etc; and see where you have power and where there should be power but isn’t. But basically, it sounds like there is no power getting to the panel. This could be caused by no power at the battery, a blown fuse, disconnect switch in the wrong position, a broken wire, bad ground, etc.
If you run wires temporarily directly from the battery to the panel does it then “light up”/function? That answer will clue you in on where to look next.