Category Archives: Navigation Lights

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.


Manitou Pontoon Boat Wiring


I am working on a 2005 22" Manitou Osprey Pro. Is there any source for obtaining a boat wiring diagram for this pontoon?

I just recently purchased this and have been trying to fix some electrical issues. Some are relatively straightforward.

Manitou Pontoon Boat

The pontoon's stereo speaker color codes matched the vendors color codes directly, but the stereo's power hookup did not - both yellow and red leads from the stereo were tied to a the pontoon's solid red wire. There was also a red wire with a yellow tracer in the same (stereo) wiring bundle of the pontoon but it was just clipped. Is one of the these a direct battery connection and the other one an on/accessory connection? The stereo wiring diagram shows two positive connections one labeled battery and the other labeled ignition - I don't want the stereo on all the time. The sun has faded all the indications of position for the ignition switch and all the switch/breaker functions. I don't even know if the ignition switch has an accessory function/position.

I don't know if the 5 function switch panel is a standard wiring. Is there a standard layout for the switches? Since the stereo speakers and power seem to follow the standard color codes for front -rear and power, is it safe to assume all the lights, horn and other accessories follow some standard of wiring? If so what are those standards and where can I find a standard schematic or wiring diagram for those standards?

I can't wait to get out fishing on this pontoon - it has an installation for a trolling motor battery in the console with direct wiring to an outlet mounted at the bow for the trolling motor (no battery installed yet) - there doesn't seem like a way to charge this battery from the engine's alternator/charger. Is there a way to connect this battery to the the engine's alternator but not allow the trolling motor battery to try to start the main engine? I don't what to run the higher gauge wiring for that. I just want to use the trolling motor battery for the trolling motor and accessories when the main engine is not running if that is possible.

I would like to develop a wiring diagram for this pontoon but I would hate to have to start from scratch and trace out the circuits by trail and error.

Any help would be really appreciated.


It sounds like a previous owner was doing some wiring modifications. We know the Manitou crew very well, and it is not like them to have hidden wires clipped off in their harnesses.

The key switch accessory position question is based on the brand of the engine on your boat. The easiest way to tell is to turn the key switch. It will either have 3 positions (OFF-ON-START) or 4 position (ACC-OFF-ON-START). If the key has an accessory position, it will have an A or ACC on a tab on back of the key.

There is not a standard layout for the switches on your helm. I would consider calling Manitou in Lansing MI to see if they have replacement panels for your boat that would have the proper labeling for the panels.

Here is the common boat wiring color code used by most OEM boat builders, including Manitou. You should be able to use this to trace down any wires on the boat.

If you want to charge the trolling motor battery while the engine is running, you will need to run some larger wires between the starting battery and the trolling motor battery. This wire size is based on the size of the alternator on your engine. Most VSR smart battery switch systems are capable of handling 125+ amps but the limit is the size of your alternator. If you alternator is less than 20 amp, the VSR is almost a waste of money. You will need to run your outboard at full alternator output for nearly 3 hours to replace what the trolling motor can draw in less than 1 hour.

Hope this helps,


Sled Boat Wiring


I have a basic 16.5 aluminum open river sled with a single engine. Currently the motor runs off one 12v battery with a manual bilge pump switch hooked up.

Koffler River Boat

I would like to add a second battery for:

  • Electric trolling motor
  • Navigation lights, to be installed
  • Bilge pump to this battery
  • Fish finder
In addition I would like to add a 12 volt two bank marine electrical boat battery charger for both batteries. I will add a 6 position fuse panel to the mix.

My questions or concerns:

Any interaction between the 12vdc system and the 120v battery charger to insure that I don’t get a ground fault. Would adding a battery switch assist with this potential problem or will a bus bar be necessary?

Thank you for any input,


Since your system is 12 volt only, I would connect all of your grounds together, including your batteries, at a common bus.

You will only trip a ground fault outlet if there is a fault from ac hot to boat ground and the boat is connected to earth ground.

If this happens it will not matter if you have a battery switch or not.

Hope this helps.


Crestliner Wiring Upgrade


Could you please check out my homemade boat wiring diagram? It’s for my 17.5′ Crestliner Fish Hawk.

As you can see, I added and wired the two Attwood battery selector switches and a fourth battery to the system (Battery 2) and wired all the batteries in parallel. I also added the Blue Seas fuse block, all lighting, fishfinder, trolling motor, etc.

Crestliner boat wiring diagram

Click to Enlarge

My goal here is to be able to run the trolling motor off the extra battery if needed and/or to be able to start the motor with the extra battery if the main died. Also, to run all the lights off the extra battery for night fishing. I’ve yet to turn both switches to “both” because I’m not sure if that would be bad for……..everything.

I’m obviously an amateur at this so was wondering if you think it’s a safe setup assuming all the fuses, connections, wire gauge, etc. are kosher? I haven’t had any trouble yet but I’m a little nervous about burning something up.

I’d really appreciate your input if you can decipher the wiring diagram.




I would make a couple of minor changes:

  • Move the trolling motor circuit protection to the trolling motor side of the switch.
  • Add circuit protection for the Blue Seas fuse panel at its connection location to the boat battery switch.
  • Use the same size boat battery cables for all of your battery link wires. You call out 4/0 for the positive lead (I would assume you mean 4 AWG) but not on any of the other cables.
  • If the trolling motor batteries are near the bow of the boat I would consider adding circuit protection at each end of this wire to help reduce the risk of a catastrophic fault.

Hope this helps,



Thanks for the help Kevin. I’ll do all of that.

Also, I was wrong about the battery cable being 4/0, its actually 1/0 welding cable.
Thanks again,



Most people don’t use welding cable on boats or cars because it is not oil resistant.


Light Switched


My boat’s navigation light switch is spliced into the negative wire.

Is this acceptable or should the switch be rewired into the positive wire. The positive wire is fused with a 2 amp fuse. Bow light

Your help will be greatly appreciated.



Although it is not a common practice, there is nothing really wrong with switching the negative lead instead of the positive lead.

The best practice is: source of power, circuit protection within 7 inches of power supply, switch, device, ground.

Hope this helps,


Nitro Navigation

I have a 2010 Nitro Z7. When I tried to use the navigation lights for the first time they wouldn’t work.

I checked the fuses. The fuse box isn’t marked as to which fuse is for the lights, so I had check them all. The last fuse, a 5 amp, was blown. So I plugged another 5 amp fuse in and it immediately blew.

What is my problem?Nitro bass fishing boat

Please help


Hi Dean,

There is a short in the circuit that is causing the fuse to blow.

Trace the wire leaving the fuse panel. It should go from the fuse, to the switch, and to the device.

If the switch is not turned on, but the fuse still blows, the problem is between the switch and the fuse. If the fuse only blows when the switch is turned on, then the problem is between the switch and the device.

Hope this helps,

Backward Boat Wiring?

Hello Kevin,

I am trying to replace the white all-round navigation light on my fishing boat wiring.

My old light had two wires, blue and black which were connected to a black and gray on my boat. My new Attwood light has three wires. One black and 2 red labeled rear and aft. Attwood LED all round white navigation light

How do I wire this?



Hi Tom,

Connect the black to the black and both reds to the blue.

Hope this helps,



I appreciate your quick response, but I tried that and it didn’t come on.


Hi Tom,

Is the new light one of the Attwood LED navigation lights?




No, the package doesn’t designate it as led. It’s titled as “Anchor/Stern Light Combination.”


Hi Tom,

It may be polarity sensitive and your boat may be wired backwards.

Either check the black and blue on your boat with a meter or try hooking up the black on the light to the blue on the boat and the reds on the light to the black on the boat.


Boat Wiring Size


Thank you for your answers to so many electrical questions. I plan to redo my fishing boat wiring and have a couple of questions.

My 1977 18 foot Starcraft has an outboard motor with it’s own circuit and will not be involved in the rewire.

My current marine electrical has a battery in the back of the boat, approximately 16 feet from the fused, marine electrical switch panel.Click to download Kevin's boat wiring size calculator

The old boat wiring is a rat’s nest with each circuit wired individually.

I will be using the standard small boat items: a depth finder, FM radio, bilge pump, navigation lights (bow and stern), gauges and a rear-mounted gas tank.

I would like to run a duplex cable from the rear battery to the switch panel. The total duplex run would be 32 feet and the total amp draw should be no more than 30.

I think I need a 10 AWG duplex cable for the 30 foot run and 16 AWG boat wiring for leads from the switches to the instruments (+) and bus bars (-)?

Does this sound right?

Thank you for any help you can provide.


Hi Tom,

I would recommend using my boat wiring size calculator to answer your wire size questions.

  • Leave the voltage drop percentages in column B and G alone.
  • Enter the current draw of you switch panel devices in column C and H.
  • Enter you total wire length run in inches for each device (switch to device and back to ground) in column D and I
  • Enter your total wire length run in inches for the panel feed (battery to panel and back to battery) in cell 25D – 384 is your guess.
  • Your wire sizes will be in Column E and J.

Let me know if you have any questions,


Navigation Light Short

Hey Kevin,Attwood is the world's top manufacturer of navigation lights for marine electrical.

I just bought a 1987 Fisher bass boat with a 1989 110 hp Johnson outboard.

The boat navigation lights had been removed but the light wiring was still running up to the front of the boat. I bought a new Attwood LED navigation light and connected it (pretty sure I did it right) but the navigation light will not work. The white all round anchor light does work when I turn the switch to just anchor lighting and navigation lighting.

I followed the boat wiring for the lights and found that the negative wire was tied into the main negative wire going directly to the boat battery (this was connected). After those two wires meet, it appears the wiring coming from the two is supposed to be connected to a fuse but it was not.

There were two fuses open, a 20 amp and a 10 amp. As soon as I connected it to the 20 amp, the fuse blew. There was a spark when I connected it. I have no clue where to go from here.

Any advice would be greatly appreciated.



Hi Tommy,

It sounds like there is a short in your marine electrical between the fuse and the light.

You can either try to trace down the short or replace the wire. Sometimes it is much easier to replace marine wiring than to find the problem. Make sure to use circuit protection at the power source to protect the wire if a short happens again.

Happy wiring,