Cabin 12 V lights not working

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SlowBoater

Newbie
Joined
Sep 16, 2014
Messages
3
Location
Canada
Hi
I have just purchased a 1978 Mainship 34 and my cabin lights don't work . I didn't get any manuals with the boat ( wiring diagrams). Does anyone have any suggestions or access to wiring diagrams ?
Thanks Slowboater
 
Check for fuses or circuit breakers. Check the bulbs.


Didn't the surveyor catch this?
 
Not likely that any diagrams that did exist for the boat in 1978 would necessarily reflect the boat as it is currently.

I suggest starting at the DC panel with a multi-tester and start checking circuits and tracing wires.

I don't know your current experience level, so please don't take offense.
- Check to see if there is power to your DC panel.
- Check to see if there is a breaker for cabin lights and that it has power and is working
- Then check any switches for the cabin lights
- Finally check bulbs.

Smarter folks than me might go in the opposite direction.
 
Greetings,
Welcome aboard. Mr. SB. So the REALLY easy cheapest things first before you go tearing into wiring. Could be as simple as a bunch of burnt out bulbs or a fuse (as already mentioned).
 
First move might be to check your batteries. If they are dead, DC won't work.
 
The surveyor on my first trawler had the same comment. In addition to the breaker on the DC panel and switches on each light, there were small switches next to each entry door that turned them all on orl off. I discovered what they were when I turned one on to see what they did and there was light.

Tom
 
You might assume that there's an electrical problem if none of the 12v lights work, but a ridiculously simple first step is good advice. The seller of our boat kept things in very good shape generally, but I noticed none of the stairs and flybridge courtesy lights worked. Naturally I assumed it was a circuit or switch problem, but turned out he just never used or cared about the ankle-high courtesy lights and every single one of the bulbs had simply burned out and had never been replaced.
 
On electrical start at the source of power and following it through to the device. I went through this with quite a few circuits on my Marine Trader. I quickly realized it was the red wire. But then, they're all red on a Marine Trader...

I found burned out bulbs, corroded sockets, broken wires, disconnected wires. If you don't have any experience with 12v systems, there are some good basic books such as the 12V Bible that can give you logic to tackle just about anything.
 
Start at your battery and work out with a DVM. If you find a break, you've found a culprit. Fix, test and continue until you reach the light or it turns on, whichever comes first.
 
Just in case you haven't told us the whole story, many cheap LED replacement lights are polarity sensitive and won't work if the positive and negative are reversed. Try a brand new incandescent lamp in one of the sockets. If it works and the LEDs don't, you will have to reverse the wires to each socket.
 
Just in case you haven't told us the whole story, many cheap LED replacement lights are polarity sensitive and won't work if the positive and negative are reversed. Try a brand new incandescent lamp in one of the sockets. If it works and the LEDs don't, you will have to reverse the wires to each socket.



Absolutely.
 
Don't get me wrong but first... check if you have put the "Lights" breaker ON on the DC panel. :)

L.
 
All of the cabin lights or just certain sections? The overhead lighting in the main cabin? Forward cabin?
 
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