Fishing Boat Wiring Solutions

Kevin Hannula answers your questions about fishing boat wiring and marine electrical.

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Goner Gauges


I have a problem with dead gauges on my old aluminum fishing boat.

Last year the tachometer and gas gauges were the only two working. The speedometer, trim gauge, and volt meter did not work. As the year progressed, the tach started to stay in one place and the gas gauge stopped all together.


When looking at the connections for the gauges they are plugged into the back of the gauge except for the gas gauge which was replaced two years ago and it has wires connecting it to the boat wiring harness. I have checked and replaced all the fuses and looked for any loose connections that I could see.

What should I look for now?

Thanks for your help.


If they are all dead, it is probably a bad power or ground connection.

Using a meter of a test light you should be able to measure 12 volts between the purple and black wires on all of the gauges when the key is on.

Since this is an older boat, the speedo is probably a pitot style that works off of water pressure. Check the pickup on the transom to see if it is plugged.

Hope this helps.


Nitro Nuisance

Boat Wiring Guys,

I need your help with a 1997 Nitro 640 LX fishing boat that I just purchased.

Nitro 640LX

When I put the red/green navigation light into the plug in base at the bow, it doesn't come on, but causes one of my gauge lights to light up and stay on.

Any thoughts on where this might be going wrong?



The ground wire for the dash panel area is no longer connected. Because of this, the dash is grounding through the filament in the red/green light.

Run a test ground wire from the battery negative to any ground at the helm (maybe a gauge) to confirm.

Hope this helps



Thanks for the quick response,

You were right about the ground wire. We found and fixed that, but we have another problem now.

There is a large wire with a plug that goes into the motor that there is apparently a short in.....when we turn the ignition on, it will not do anything sometimes until you move that large wire around.

What is that wire called that plugs into the motor and apparently goes to the switch as well?

We need to figure out what to get to replace it.

Thank you,


It sounds like it is your main engine harness plug.

Most of those are modular and can be taken apart. This means that you may be able to just replace some terminals instead of replacing the harness.


Bass Boat Gauge Dimmer

Fishing Boat Wiring Guys,

I really appreciate all of the work that you guys put into your site. I'm guessing that it has kept loads of boater from doing very stupid things.

Tracker 175TXW bass boat

Here's my question...

I have a 2013 175TXW Bass Tracker and would like to add a dimmer switch to the instrument cluster lighting.

Could you tell me what color is the power wire for the lights? Or are the lights powered off the power wire for the individual gauges?

Any info would be helpful.


According to boat wiring color standards, the lights should be powered by the blue wire. But, I would recommend that you test with a meter before cutting anything.