Re: wiring diagram for trim gauge in dash ?
No magic here at all. All of the gauges are wired exactly the same except for a speedometer, tach and voltmeter. But, all of them require +12 volts when the key is on, all of them require a ground connection, and in the case of fuel, temperature, trim and tach, all require an sender signal ("S" terminal on the gauge). All of those connections except the "S" are daisy chained from one gauge to the next so if only the trim isn't working, that gauge is missing +12 volts, ground, or the "S" signal from the sender. DO NOT replace the gauge as it is more than likely the sender on the engine or the wire from it to the gauge, or wiring to the sender that is the issue.
