Can someone explain how 2-contact navigation light sockets work?

[Big6ft6]

The navigation lights do not work on my boat. The bulbs have the two contacts on the bottom. When I test with a volt-meter I get 12 V across the two contacts in the fixture/socket.

My question is, with this type of light/socket does the metal socket sleeve itself (the part the bulb slides into) play any part in the circuit? In a household bulb, there is only one contact on the bottom of the bulb and the screw-in base must have a good contact with the metal socket threads of the fixture to complete the circuit, but with these boat lights, is the metal socket itself part of the circuit at all? Or is its sole purpose to provide a secure grasp of the bulb.

Do I need to clean the walls of the socket/fxiture to provide good connection with bulb base??

Sorry for using the wrong terminology.

 

[H20Rat]

The metal sleeve doesn't play a part... Just because you get 12v doesn't mean a light bulb will light up. If you have a REALLY bad connection somewhere, it still will show 12v, but will only be able to support .0001 amps without dropping the voltage so low a light bulb will never light.

Before that though, going to ask the obvious... have you tested the light? Take some jumper wire and wire up the light pole directly to a battery first!

 

[Big6ft6]

Thanks smokingcrater! I was worried about low current, but not sure how to test that (resistance in the wires?). My bow light is just a pigtail and a socket captured in a chrome housing. should I cut the pigtail and put against a battery? My stern/anchor light is on a pole that plugs into a socket with pins in it. Any tips on how to create leads that I can hook to a battery and insert into the base of my stern light pole?

Thanks

 

[midcarolina]

I wouldn't cut the wires just yet........ do you have a 12 volt test light? if so pull the bulb and use the test light to see if the 12v lights the test lights bulb.....that will put a load on the wiring/socket to simulate the light. if it doesn't light check all electrical connection pos and neg for bad/dirty connections. if it does light either the bulb or the socket is faulty.

 

[Big6ft6]

Thanks All...checked all wires and found the ground wire had snapped off of the negative junction block way back behind the gas tank. I crimped on a new eyelet terminal and attached it directly to the negative terminal on the battery....viola! I have lights and horn now!

I was a little stumped at first since I'm used to cars where everything is grounded the frame/body...when I looked at the switch panel and could find no ground wires?? It all makes sense now.

 

[Barramundi NQ]

Just remember to never ground a wire to an aluminum hull. You can ruin the hull in no time because the current in the alloy hull will begin to disintegrate in front of your eyes as the water will create electrolysis and eat out your hull where it touches the water, especially salt water!
gidday from OZ
Kerry