Hi, two days ago i was fishing, i noticed that my icommand gauge pop-up showed 0% and after some second again 25% which was my trim position. After some moments again the same. 0% and after a while my actual trim position. Yestarday i took my multimeter and checked the trim sender unit resistance. IT seems to work because the readings i had was between 10ohms and 93ohms from full down to full up. Also there is continuity in every cable to the emm and after that it is the nmea network and works fine with every other reading functional. I am wondering what this could be. I am concluding to the trim sender but i wonder why the resistance is changing? Trim sender fuse has 3 cables, white/orange stripe, black and green. I putted my multimeter between white/orange and black to measure the resistance. Engine is 130hp Etec 2010 model with icommand gauges. thank you.
Your year engine uses a current flow based trim reading as opposed to the G2 which is a voltage based system. My suspicion is the momentary zero trim readings you observe are due to interruption of current flow through the circuit momentarily.
You could verify the interruption with your multimeter used in ampmeter mode. Once verified, you could use voltmeter mode to trace along the trim sender signal path to determine where the voltage source stops when the condition occurs. Voltage for the circuit originates at the helm and ground for the circuit ends at the engine on the black wire you described on the sending unit.
I would check for voltage interruption first at the 3 pin Deutsch MWS connector at the engine (white/tan I believe) and then at the trim sender white/ connection. If voltage goes away at the MWS connection, the problem lies from the engine forward in your boat. If it goes away at the trim sender connection, the problem lies within the engine components. If neither locations reveal a voltage loss, the issue lies within the trim sender and/or connections to ground.