Grady Canyon 306 owner question re shore power

[Sardinia306Canyon]

Still trying to figure it out, but definitely appreciate your reply.

First to make sure: Do you have electric steering or hydraulic steering with hoses and pistons in front of the outboards?
If you have hydraulic steering then the steering will work always but you need a lot of force to turn the wheel.

You should have verified by a pro what was and will be the problem to loose the steering, joystick is somehow understandable, but the whole steering system is a bit wired and also dangerous.

When paralleled and the steering started to work again would most likely mean that the house battery where very weak of dead.
But, as you have 3 batteries i guess you have the same battery system as i have, stbd engine and house together on 2 batteries and if both batteries where low the starboard engine would not had cranked if stbd battery switch was on 1 (but maybe on 2 or ALL).

My manual states that the stbd side battery switch should be on 1 and the port side switch on 2 and i guess it's the same for your newer model.

The dealer who should know the boat should verify
how the batteries are cabled (ex owner could have changed something)
if there is a ACR or similar device to combine and/or select the weaker battery to charge
on what battery (port or stbd engine) the Yamaha Steering is connected if it has a own connection and is not powered by the engine harness
if there is something else than the bilge pumps connected when battery switch in OFF what could drain the batteries
if there is a weak or intermittent contact on the power line for the steering

Chris