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Author Topic:   Navigation Lighting Intermittent
oakpwr posted 10-12-2007 08:39 PM ET (US)   Profile for oakpwr   Send Email to oakpwr  
Okay. This one is driving me nuts. I had problems with my stern light, checked the switch and it seems okay. Checked the power coming out of the bulb area and it has power. Checked the bulb for continuity and it's okay. Checked the stern light pole with the bulb in it for continuity and it's okay. But when I try to turn the switch on there is no light. I tried my buddy's stern light pole and it also didn't fire up.

How the heck do I get this to run correctly? I used the clamp on stern light to get me by the other day but I'd like to have the switch one actually work.

My two 12-volt batteries are registering 19 volts. It is also measuring 19 volts across the top of the stern light, is this normal? How is it possible that a 12 volt battery is giving off 19 volts?

Any ideas or suggestions are welcome, I already put some dielectric grease on all the fittings after the first failure.

Chuck Tribolet posted 10-12-2007 09:25 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
What boat?

I'd be very suspicious of your voltmeter. A 12V battery won't
make 19V in any failure mode I know of. And 19V would make
for a VERY short bulb life.

So try another voltmeter. And another measurement to try is
across the bulb contacts with the bulb in. I'm suspecting
that there's a high resistance across the plug contacts, or
where the wires attach to the plug. You'll see a low voltage
at the bulb with the bulb in, and a high voltage with the bulb

I fought this sort of problem for a couple of years, finally
gave up and ran a contiuous piece of boat cable from the
switch through the tunnel and up the mast to a new socket.
ZERO problems since (seven or eight years).


jimh posted 10-13-2007 09:14 AM ET (US)     Profile for jimh  Send Email to jimh     
One of the most admirable characteristics of electrical circuits is that they always obey the laws of physics. This allows rational trouble shooting. If the light bulb is not illuminating it is probably not receiving enough voltage to cause sufficient current to flow through it. In 12-volt electrical systems it is possible for very miniscule amounts of corrosion to impede the flow of current. The remedy is to clean and restore all connections and contacts in the circuit.
oakpwr posted 10-19-2007 03:42 PM ET (US)     Profile for oakpwr  Send Email to oakpwr     
thanks guys, I'll give that a try today. Im also redoing the glass fuse box to a blade fuse box, it's going to be a day of labor :)
L H G posted 10-19-2007 09:55 PM ET (US)     Profile for L H G    
The wire between your switch and stern pole is bad, even if it looks good.

I had the same problem with bow light wiring on my brand new 1989 Outrage 25, where the wiring is run under the rub rail insert. The lights worked intermittently for 5 years, no matter what I did. Finally, I determined it HAD to be in the wiring itself, and pulled off the rub rail to expose the entire length of wire. It looked good, no cuts, abrasions etc. So I started feeling it for an internal wire problem. Sure enough, there was a section where the wire itself was barely continuous and frayed. Cutting it open revealed simply a defective run of wire from the manufacturer where the insulation was perfect, but the wire was broken inside.

Ran a new 2-strand 16 ga wire cable, no problems now in 15 years.

oakpwr posted 10-20-2007 04:18 PM ET (US)     Profile for oakpwr  Send Email to oakpwr     
I ended up putting in the new blade type fuse box and got rid of all the wires that I could determine were not functional. My whaler was made around 1972. It looks much cleaner inside now. I redid all the wiring for the stern light, and, low and behold, it fires up no problem now :).

When you guys are redoing your [bow navigation light wiring], are you running the wire under the rub rail? Is there another place you can run it easily? [Running wiring under the rub rail] seems [painful] since it [the wire or the rub rail?] tends to break easily.

jimh posted 10-20-2007 05:22 PM ET (US)     Profile for jimh  Send Email to jimh     
I am not clear if you are concerned about the wire breaking or the rub rail breaking. If you use a high-quality marine wire it should have many strands and not have a problem in breaking due to flexing. If you use a poor quality of wire and it has only a few strands, you may have problems in the future with fatigue from movement.

The vinyl insert in the rub rail is usually pliable. If you have problems removing it I recommend using a hair dryer to heat it. With some moderate heat the vinyl rub rail insert becomes much more flexible and pliable.

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