Lingering Light

Boat Wiring Guys,

I put in new VHF radio into my sailboat. The installation seemed to be successful except...

Now when I turn off the marine electrical panel switch for the VHF, the green light from the breaker goes out but not right away, slowly turning off in about half a second.

Is there any problem with this? Did I screw something up?



It is not a problem.

The light in the switch gets power when the output side of the switch has power. The residual light is caused by a capacitive charge that is in the VHF radio. This capacitor in the radio helps with noise and voltage spikes but will give the appearance of voltage on the power wire which makes the light stay on.

Hope this helps

Sound of Silence


I recently purchased a 2006 Chaparral 236 SSI knowing that the boat’s stereo didn’t work.

After replacing the fuses on the stereo and checking the fuse panel underneath the dash, I didn’t find any breakers popped. But, I was still not getting power to the stereo.

I went ahead and bought a new stereo to put in, reconnected the wires – and still have the same issue. I am trying to figure out where to start troubleshooting next.

I have pulled out all the speakers and checked their connections and they are good. My owner’s manual doesn’t help in locating anything else I could check such as ground or the which lines go where.

If you have any tips or a place for me to start I would appreciate it.

Thanks for your time. All other electronics besides speedometer and tach are working fine (that would be another question haha).


Hi Jon,

The best way to solve this is with a handheld voltmeter and confirm that there truly is 12v power at the stereo connection when you are trying to turn the stereo on.

There is probably a loose connection or corroded wire that is causing the problem.

Hope this helps,


Wire Whereabouts


I recently bought a 2007 Smokercraft SunChaser 820. The stereo didn’t work when I bought it – a SeaWorthly SEA MBB126 radio with an amplifier. Sunchaser pontoon

I unplugged the amplifier connection from the boat wiring then also lost my front front red and green navigation lights. After successfully connecting the speaker wires to the new Sony harness, I now can’t seem to find the old wires to splice my battery and ignition wires from the new – or figure out how to get my navigation lights back on. I am a marine electrical beginner at best.

I realize the radio needs power and battery to backup memory. Now that I can’t find any wires from the old amplifier, what is the easiest way to run a line to power and battery to get the radio working?

Any help would be greatly appreciated.


Hi Bob,

My guess is the forward navigation light wires were connected with the same plug as your forward speakers. Smokercraft is a first class boat builder that uses standard boat wiring colors, which means Gray/Green for forward navigation light power and black for ground. The speaker wires will be a different type of wire that will not match the rest of the normal boat wiring.

The ignition switched power wire is going to be purple and most of the time they use yellow or red/yellow for stereo memory.

If you are running new wires back to the battery, make sure to add an in-line fuse or circuit breaker at the battery. You wouldn’t want you new wire to go up in smoke and disappear like the old ones.




I have a Mako 191 that is nine years old.

The VHF radio and depth finder do not work. The boat batteries are fine and everything else in the marine electrical system works. I also checked the boat’s circuit breakers and they are fine as are the two inline fuses.

The radio and depth are connected to same switch. How do I know if it is the switch that has gone wrong, vs. other connections/wiring. And, if it is switch, how do I replace?



Hi Sandy,

The best way to track down your marine wiring problem is with a digital multimeter. You will be looking for 12 volt power at the connector when the radio is turned on.

Since both devices have quit, it would only make sense that it is either the switch, one of the switch connections, or the ground wire.

Boat builders only use a few different switches. The most common are made by Carling Switch. If the switch is bad, email me a photo and I will tell you what kind of switch it is.

Hope this helps,


Dance Dance Devolution

Hey Kevin,

I know you’re a marine electrical engineer, but I have a marine audio question and I’m not sure who to ask. If this is not your thing, I completely understand. If you have time, and you can answer my question, I would really appreciate it.
I have an old 1976 double decker party barge with the following audio system:

  • Rockford Fosgate RFX9700CD head unit (40w x 4 peak, 17w x 4 RMS) mounted in the driver’s console
  • Four Poly Planar MA 9060W box speakers (rated for 100w max, 60w RMS) mounted on underside of upper deck
  • Premium 16 gauge marine-grade speaker wire
  • All new tinned marine wiring throughout the whole boat (much of which came from your retail site)
  • One Pyle PLMRBS8 powered subwoofer mounted under a seat

I completely restored this boat in the spring of 2010, and I installed all this stuff new out of the box at that time.

The problem I’m having is that the radio is cutting out a lot if the volume is turned up as loud as you would want it when people are dancing and having a good time. At normal volume levels, everything is fine, but as soon as we turn it up for a good dance song, it starts cutting out. Here’s the four possible reasons I thought of:

  1. Do I need more power for those 4 speakers? Could that be the problem?
  2. Could the head unit be getting too hot? There’s not really any ventilation in that center console, although the center console is usually mostly shaded from the sun by the upper deck.
  3. Could the fuses on the back of the head unit be going bad, or something like that?
  4. I thought maybe it could be a short in the ipod adapter wire, because when you more the wire around sometimes it seems to get a little better, so I ordered a new one of those today, just in case that’s the problem.

If you have a minute and can answer my question, I really would appreciate it. Thanks for all your help in the past.


Hi Paul,

The current draw of the radio is more than your marine electrical can handle; the louder the volume, the higher the draw, the more the voltage drops. When the voltage gets too low, the stereo shuts off. When the stereo shuts off, the voltage goes back up, and the stereo turns back on.


Run a separate, 12 awg power wire and ground for the stereo back to the battery (or boat battery switch and ground bus) with an in-line fuse at the + battery connection.

This will solve your problem.



Thank you very much. I hadn’t thought of this. If I may, I’d like to ask another question to be sure I know how to fix it the way you suggested.

The wiring that’s in place for the stereo is using the complete pontoon boat wiring harness from EzAcDc, running through one of your switch panels on the driver’s console, and then to your smart battery switch (2 battery system). All the grounds go to a ground bus. The wiring harness has an in-line fuse on it, but I think that’s for the whole harness, not specifically for the stereo.

Are you thinking that the power wire for the stereo (in the pontoon wiring harness) is too small? So I should just swap the power and ground wires for the stereo to larger wires, running the ground wire to the ground bus, and running the new power wire through the switch panel, then to a in-line fuse, and from there directly to the secondary battery’s positive terminal? This will bypass the smart battery charging system, but that’s fine with me if it will fix my problem.

Would anything change about your recommendations if I decide to put a 50×4 marine amplifier on the 4 speakers? I believe you are 100% correct about what my problem is; however, I also believe that the 4 Poly Planar speakers would sound better with additional power. Like I said, they are rated for 60 watts RMS, and they are only getting 17 watts RMS from the head unit.

Thanks again. You’re awesome.


Hi Paul,

Isolating the power and ground for the stereo will solve your problem. The 16AWG is adequate for a smaller stereo, but once you go larger, it is not enough.

I would run the power back to the battery switch and connect it to the same switch stud as your boat accessory harness. The 4′ of 2 AWG red from the switch to the battery will not effect the voltage drop. The ground can run back to the ground bus for the smart switch system.