Accessories don't work when boat in water

[boatsmith]

I have an Aluminum Hull Tracker. The FM radio, lights, pumps, depthfinder worked when on the trailer, but not after I launched in the lake. Think its a ground wire between battery and fuse panel. How do I test it? How do I thread a couple new wires through from the rear battery to the console in Tracker ProGuide V-175? No problems with the engine.

 

[dingbat]

I have an Aluminum Hull Tracker. The FM radio, lights, pumps, depthfinder worked when on the trailer, but not after I launched in the lake. Think its a ground wire between battery and fuse panel. How do I test it? How do I thread a couple new wires through from the rear battery to the console in Tracker ProGuide V-175? No problems with the engine.

This doesn’t make any sense.

The diagnosis would make more sense if the circuit worked on the water (conductive) and not on the trailer.

Check for continuity between the primary ground terminal on the fuse panel and the hull. Then check between the ground terminal on the battery and the hull.

If you have continuity at both places you have a ground problem, but it not causing your lighting problem. Using the hull of an aluminum boat as ground plane sets up all kinds of long term corrosion related issues.

If you don’t find continuity between hull, fuse and battery as you should, run a temporary wire between the ground terminal on battery and fuse panel. If the problem persists, you have a power problem.

If the wire solves the problem, something happened to the existing ground it needs repaired or replaced

 

[boatsmith]

This doesn’t make any sense.

The diagnosis would make more sense if the circuit worked on the water (conductive) and not on the trailer.

Check for continuity between the primary ground terminal on the fuse panel and the hull. Then check between the ground terminal on the battery and the hull.

If you have continuity at both places you have a ground problem, but it not causing your lighting problem. Using the hull of an aluminum boat as ground plane sets up all kinds of long term corrosion related issues.

If you don’t find continuity between hull, fuse and battery as you should, run a temporary wire between the ground terminal on battery and fuse panel. If the problem persists, you have a power problem.

If the wire solves the problem, something happened to the existing ground it needs repaired or replaced

So I remove the ground wires from the terminals at the fuse panel and at the battery and check continuity between the wire terminals and boat hull? Continuity means ground wire issue. I will also have to detach the other ground wires from the fuse panel, (pumps, radio, lights, horn, etc) correct? I'm sure they are all connected back to the battery. If it were a power wire short, it should blow fuses or trip the main breaker on the red wire. But I suppose it could be power leakage through a resistance. Why did it work on the trailer? Maybe its a matter of wires moving on and off of a contact point? At the last check I had proper voltage at the accessory feeds that checked. There is a relay on the CD/radio feed which I don't understand.

 

[dingbat]

So I remove the ground wires from the terminals at the fuse panel and at the battery and check continuity between the wire terminals and boat hull?

You don’t remove any wires to check ground.

Check for continuity between the battery or accessories panel ground and the hull.

There should be no continuity. If there is, you have a grounding issue not related to your power problem.

Have you put a meter on the power connections at the accessories panel when the power if “off”? What are you seeing there?

If your seeing 12.7 volts at the panel and nothing works you definitely have a grounding issue. Run some wire from battery ground to ground terminal on accessories panels don’t see if that solves the problem.