ST4000 low bat ? -check wiring first
Don't know whether in fresh or salt water, but would suspect a corroded connection. Either wiring to battery or control unit to wheel controller. Wiring at wheel was encased at the factory. My control head on H34 was close enough that no splicing was needed, so first user serviceable screw up area would be to recheck all connections at control head. First measure the 12V lead at head. Then, follow supply wires from head back to battery. The 4000 has a current limiting 5 amp fuse inline, installed by user, and typically draws .5 to 1.5 amps while tending(turning)helm, and 60 MA in standby.. so it would take 10 hours to suck the battery down. But if you have a bad connection, or prior owner installed with small wire, high resistance would show up at the unit as low battery voltage. Spec is that low bat alarm comes on at 10 /-.5 volts, which is a well drained battery. I think that if you measure your battery bank you will find that you have plenty of juice, so then feret out the bad connection. By the way. wire specs for ST 4000 are 18AWG 8 ft, 16AWG 13 ft, 14AWG 22 ft. On the back of the control head, you will find the wires to check labeled: 12V - (2 wires) and Drive (2 wires)