Broken wire to steaming light

[Jim Cate]

My experience: it is seldom a failure in the body of the wire. Almost always it will be at the connection(s) at one end or the other, so those are the places to check first.

do you know what variety of lamp it is? And what type bulb? I had one years ago that had a festoon bulb that was unshielded from the wx, and it had lots of problems (as you might have guessed). If yours is that type, consider replacing it... money well spent!

Jim

[Squanderbucks]

If you do decide to replace the wire possibly the old one(s) can be used to pull through the new ones.
Also with multimeter check to see if the problem is in the Hot + wire or ground side.
Take out bulb and put meter on one bulb socket and the other to any ground (mast bare spot) Ind see if any current. Do same on other socket terminal.

[Spot]

Similar situation here, figured it was better to buy a bulk spool of marine 14/2 wire and redo the 24 foot (8 meter) runs rather than keep or troubleshoot the old un-tinned wires.

[Bycrick]

The older AquaSignal incandescent nav lights have spring-loaded terminals in the base. If the wire gets stiff with age, or there’s any corrosion around the terminals,the spring may not be able to push the terminal up to contact the light bulb terminals. If this happens, the bulb will test good and you’ll have 12 volts across the terminals, but the bulb won’t light. Even with new wire, you have to make sure there’s enough "slack" between the terminals and the wire seal to let the terminals "float."

[Cadence]

Originally Posted by JoeRobertJr

I would do some voltage readings to isolate. If you have access to the wires at the compression post, you could shave off a little insulation, take a voltage reading there, and then reinsulate. That would tell you whether the problem is towards the panel, or towards the light. Then repeat to narrow down the location.

I just replaced all the wiring in my boat from panel to mast and am about to start on the mast wiring. The old wiring had become too corroded.

I would not shave off any insolation. You can stab a meter prob. through the insolating.
You might hit the spot with a dab of liquid electrical tape.

[JoeRobertJr]

Originally Posted by Cadence

I would not shave off any insolation. You can stab a meter prob. through the insolating.
You might hit the spot with a dab of liquid electrical tape.

Agreed. This is a better idea.

[Bycrick]

I would suggest that you DON'T use a digital volt meter to check the voltage. Buy or make a test light using an incandescent lamp, like a taillight bulb. A DVM draws essentially zero current. So you can have an almost completely bad connection, not enough to light your nav light, but it will show 12v on the meter.

[Clivevon]

Before doing anything too complicated (spoken as a non-electrician) I suggest you check the panel switch. You said the other lights on this circuit work OK. I assume you mean other lights on your mast such as anchor, tricolour or deck lights. They will all have their own circuits with switches at the panel - as will the steaming light.
Can you try switching off all battery power to the panel, then taking the connector off the steaming light switch & swap it with one of those other lights that do work - say the tricolour light. (first make certain you can positively identify those wires when loose - label it with some tape). If the steaming light now works & the tricolour nav light now doesnt, you know the problem is not with the wire or with the light fitting, but with the switch. A quick & easy check. Worth doing.

[Clivevon]

obviously switch the battery power back on before checking, & off again before switching the wires back where they belong....

[Scott Berg]

a TDR will tell where the open or short is within inches assuming you set the correct velocity for the wire. Most boat owners won't have one but most real pro's will. I have 2 and use at least one of them weekly. https://en.wikipedia.org/wiki/Time-domain_reflectometer