Have Boat Questions? Ask a Boat Repair Expert.
Hello. My name is Tan.
This is going to be in your connections. You have a bad or loose connection at the battery or at the dash. Check that all you battery connections are clean and tight. Be sure all your grounds are connected at the battery. Many times a ground can get left off. Poor grounds a what causes you to loose voltage on electrical components when you hit the trim switch.
The boat accessories are on a different circuit from the engine and they get battery voltage directly from the battery. So you need to verify that all these wires are clean and tight. These wires will be smaller than the battery wires 10 gaige usually. Then there is a inline fuse holder in the red wire.
Grounds are the most neglected connections on the battery.
Do these checks and post back with findings.