I finally had time for trouble shooting my system, and I am sorry to say I had little success.
i have a 21 Sport Cabin and my 1st action was to climb in under the steering console. Now I have had the boat, which I bought new, for 9 years. Fortunately I have not had to do much if anything under there in the whole time I have owned the boat.
When I looked in I was aghast, see photo.
With great difficulty I traced the wires best I could. I pulled the switch out of the console and removed the connector and cleaned the terminals.checked the boat batteries for voltage and then tried to get to the terminals on the trim tabs.
All the wires from the trim tab control box are connected to a harness of wires that go into gunnel running to the back of the boat.
In the stern the wires go into the battery compartment and then into hull. There is no access to the trim tabs so I could check the connections.
Any advice on how to get to the trim tabs, without removing them from the stern?