The Super Dash 101-B controls output if the amp requirements exceed the set levels. You can test the pump by switching to another cartridge and it is usually the pump that fails. It may run hot wired, though that’s not fused or regulated. Thus the system protecting it is preventing over draw.
Also, the grounds could need cleaned up on the terminal block at the transom. That’s a frequent issue on older boats and you may have some work to do there.