I have a 2004 218 LS that I bought new has 180 hrs of fresh water time on it. The trim/tilt works fine but the gauge is not working. This is where the problem comes in. When the trim button is pressed while the boat is running the voltage gauge and fuel gauge drop to the off position and the radio cuts outs.
Things I have tried so far:
1) The two batteries are new but I pulled them out and had them tested and both are good with a full charge.
2) Put a volt meter on the batteries with the boat off and am reading 12.8 volts
3) Put a volt meter on the batteries with the boat running and am reading 14.8 volts.
4) Put a volt meter on the batteries with the boat running and pressed the trim button and am reading 13.5 volts.
5) Disconnected the radio power and ground pressed the trim button and gauges react the same. (drop to off position)
6) Disconnected both batteries with boat running and pressed the trim button and gauges react the same.
This eliminated the batteries and the radio as the cause. I am wondering if it could be a short in the trim sending unit. If so how can I disconnect it to see if the gauges drop or not? Any suggestion for a cause would be greatly appreciated.