Code number as related to DC Circuits?

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Capt. Rodbone

Senior Member
Joined
Sep 6, 2020
Messages
178
Location
U.S.
Vessel Name
SV Stella Polaris MV Sea Turtle
Vessel Make
1978 VanDine Gaff rigged schooner, 1978 Grand Banks Classic Trawler
We have a situation where our starboard running light isn’t working and it is not the bulb. To get to the wiring I have had to remove a storage shelf, allowing access under the flybridge to wiring, etc. Not much room in there for me to crawl around and I’m a big guy but I will have to figure it out. This may be self-explanatory when I get in there and get started this afternoon, but I am wondering what this means? My manual says the running lights are code number 9 . Is that going to indicate something I should be able to find in there to check all connections? Maybe I’m going to get to the grounds and see one that’s labeled “9”or maybe on the the positive side as well?
 
That probably indicates that you will find the positive lead labeled at each end as a "9", although there may not be a label at the light (since it is obvious there). From the light, the positive wire likely leads to a switch, where you should find the 9, and from the switch to either a circuit breaker, where you will find another 9. Unless you have been doing work, etc., that may have damaged or disturbed in place wiring, the point of failure is likely at one end or the other (or at a junction in between). With an exterior light, I would strongly suspect the fixture itself (corrosion there is almost inevitable), or possibly the circuit breaker.

Note that testing with a voltmeter may not answer the question as you can still read +12 volts even if the wire is heavily oxidized / corroded. But that corrosion will create a great deal of resistance, so when the circuit is under load (ie, the light is "on"), you will not get the voltage necessary to power the light.
 
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Is this for your Grand Banks? If so, the factory used small plastic "collars" with circuit numbers where wires connect to buss connectors, and where circuits originate at the DC panel in the engine room. Disregard this if not a Grand Banks inquiry.
Regards,
Scott
 
Our anchor light failed us recently. The LED was not the issue, neither was the wiring. It was a 2mm circular black dot on the leaf spring at the button. Needed to be scraped away. At 50 feet above the deck [emoji15]
 

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