Cabin lights in forward cabin

[Steve_in_lex]

Any suggestions on where to start to track down the cause of the two ceiling lights in the forward cabin not working?  I've changed bulbs and that doesn't make a difference.  All the other ceiling lights work fine.  Thanks.

[pbyrne]

Do you have voltage in the sockets?  If not maybe check the wiring from the breaker that runs forward.

Did it ever work?  Is there anything that changed between working and not working?

Unfortunately the schematic in the manual isn't specific about where it runs...

[Ron Hill]

Steve : All I can tell you is to take the fixture apart and see if you have power (multi-meter) in the cabin light wires???   If so, then the fixture is your problem!!

A thought

[Dave Spencer]

Ron is right.  A voltmeter is your friend.  Also, the electrical schematic in the MkII manual might be helpful.  It shows the cabin lighting wiring starts at the electrical panel and runs clockwise around the boat to the aft cabin reading lights.  Assuming the wiring has not been altered and the schematic is a reasonable representation of the phisical layout of the wiring (which is a big assumption), if the lights along the starboard side of the boat are working, then the problem is isolated to the v-berth reading lights or the short wires that feed it.

[Jim Hardesty]

Steve,
I agree with Ron.  Take the light fixtures down and inspect the wiring.  If it's like Shamrock the connections were not done very well.  Also check the switches on the light fixtures.  I had to clean-up the contacts on a couple of them. 
FWIW.  Haven't had a problem since switching to LED lights. 
Jim

[Ted Pounds]

Important note: you can have voltage at the fixture and still it's not working.  That can be because you have a high resistance (poor) connection somewhere in the circuit.  So with an open circuit you get a good voltage reading, but as soon as current is flowing the voltage drop across the poor connection doesn't leave enough voltage for the light to work.

[scgunner]

Steve,

The cabin lights on my boat are wired in series so if there is a broken connection in one light every one forward of it goes out too. When rebedding a stanchion I inadvertently crushed the wires under a stanchion washer which grounded the system causing all the lights forward of it to go out. You might check that run of wires and make sure they aren't fouled on anything.

[Steve_in_lex]

Thanks all. The lights in the forward cabin used to work fine, then the port one went out a year ago and now the starboard.  These are very helpful tips for diagnosing the problem.

[Kyle Ewing]

If removing for shooting, you might consider replacing with led. Some fixtures also have USB charging which I find convenient.  I went with these:  https://a.co/d/h6H4U0v

[Jim Hardesty]

Some fixtures also have USB charging which I find convenient.

I added a cigarette lighter plug at the starboard side, that's the side I sleep on, I do like my phone plugged in there.  Been many nights I wake up and check the GPS on my phone to see if I've moved from anchor or check where the thunderstorm I'm hearing is heading.  I've tried some of the anchor alarm apts and found them lacking.  Nice idea but haven't found one that works well enough to use.
Jim

[Noah]

I digress: It would be an interesting thread on "where I sleep", (maybe there is one) but I sleep in the aft cabin and have installed a cigarette-style Blue Sea plug in the aft cabin for my phone and one in the V-berth (for guests and my dinghy air pump).

[Ron Hill]

Guys : I have cigarette lighter plugs in the Vberth; 2 in the main cabin and one aft.

However, don't buy the el-cheapo female cigarette lighter plugs.  Spend a few more $$ and go with the Blue Sea brand.  You won't regret it!! 

Don't forget to fuse that line!!!   

A few thoughts

[Noah]

This is how I fused mine using a Blue Sea fused distribution box in my nav station hanging locker. The other "thingy" in there is my 2000W inverter and the back of the inverter on/off switch.

[Breakin Away]

Important note: you can have voltage at the fixture and still it's not working.  That can be because you have a high resistance (poor) connection somewhere in the circuit.  So with an open circuit you get a good voltage reading, but as soon as current is flowing the voltage drop across the poor connection doesn't leave enough voltage for the light to work.

I must add that this is a potentially dangerous situation. High resistance and high voltage drop lead to high heat, and is a fire hazard. All connections must be either very low resistance (closed switch) or infinite resistance (open switch).

Thanks all. The lights in the forward cabin used to work fine, then the port one went out a year ago and now the starboard.  These are very helpful tips for diagnosing the problem.

I had a couple fixtures go out because the switches were making unreliable connections - a fire hazard. I found these SPST rocker switches that fit perfectly in the existing MkII light fixtures. I got some white ones, though all I see right now is black:

5Pcs On/Off Boat Rocker Switch 5Pcs 2 Pin Position Snap 12V 110V 250V QTEATAK https://a.co/d/1QzLRfy

FWIW, I also retrofitted these LED bulbs into the existing fixtures. Currently unavailable, but I'm sure Amazon has an equivalent version from another seller:

MUMENG Super Bright 10 Pack 4W AC/Dc 12v G4 LED Lights Bulb Lamps 24x2835SMD Warm White G4 Base LED Bulbs Non-dimmable 30W Incandescent Bulb Equivalent https://a.co/d/eZ6VMiL