Nav Light Problem

[Gimme5]

I'm electrically challenged so hoping someone would enlighten me with answer to a basic question. My starboard nav light keeps going very dim even after changing bulbs, which lead me to conclude it's not a bulb issue. There was a bit of corrosion (green stuff) on the contacts which I had cleaned up but that did not help. What possible causes could there be?

[Andy56]

deleted double entry

[Andy56]

Bad earth. As you are seeing corrosion on the contacts, this would be my starting point. You say you cleaned the contacts. Is that then metal to metal contact or are you adding an element of protection? Corrosion happening that quickly is not a good sign. It could be due to problems elsewhere. Possible wrong cause and effect here.
bad earth can have many reasons. 1/faulty cable. 2/ bad contact. 3/ incorrect wiring 4/ fault somewhere else. 5/depleted sacrificial anodes and there could be more

if as you say, you know nothing about electricals, diagnosis here will be extreemly hard. As a bare minimum, i would be checking the condition of the cabling/connections to the lights from start to end ie battery/switch all the way to where your playing.

why are we suddenly doing electricals in the wrong headings? Doesnt worry me too much, but it stuffs the archives up, lol.

[Gimme5]

OK so it's bad earth. The corrosion happened over 10 years but i guess I need to clean up the contacts better and see how it goes. I've already changed 2 bulbs, they'll be OK for a while and then go dim again.

[Andy56]

OK so it's bad earth. The corrosion happened over 10 years but i guess I need to clean up the contacts better and see how it goes. I've already changed 2 bulbs, they'll be OK for a while and then go dim again.

over ten years you say? I would be looking at marginal earth cable diameters. which contact is showing signs of corrosion, positive or negative? Is one of the contacts shorting to the hull? more facts means its easier to narrow down the problem

[swof63]

If they go okay after being changed then get worse, and the only thing you have done is change the globe then it’s probably the globe holder/globe interface continuing to corrode and create resistance. Could the globe holder be exposed to moist salty air?
I’d take a multi stage approach
- make sure all your wiring both +ve and -ve is good back to the switch and common neg. cleanup or replace any suspect terminals.
- clean up the contacts in the globe holder or replace the globe holder
- try and use globes with brass bodies rather than shiny chrome ones
- once globe is inserted, spray some lanotec or wd40 into the holder to try and exclude salt air
- take steps to seal the housing better. I’ve seen some with big holes where the wires go through but which unfortunately are not watertight. Also check any rubber gaskets if present.



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[scottar]

it's a bad connection somewhere - anywhere between the switch and the light itself and if it's in the negative it could be anywhere in the boat depending on how it was wired up. Start at the light and work your way back checking all connections in both positive and negative. Sometimes it is quicker and easier to just tear it out and replace it.

[Gimme5]

"......just tear it out and replace it". That thought had crossed my mind. However I've already given it another good and thorough clean up to all assessable contacts some of which wasn't cleaned the last time, replaced the globe (and it looks good for now) and I'll keep my fingers crossed.
it's a bad connection somewhere - anywhere between the switch and the light itself and if it's in the negative it could be anywhere in the boat depending on how it was wired up. Start at the light and work your way back checking all connections in both positive and negative. Sometimes it is quicker and easier to just tear it out and replace it.

[Andy56]

could always change to LED lights once and for all. Elliminate globes and globe sockets as potential problems.

[Noelm]

Yep, what he said, toss those shit globe lights in the bin, fit some decent LED lights, wire them properly, go boating......

[gazza2006au]

Pull your wiring out a little and remove the light holder than trim back your cables 10mm than strip it take a look at the cables and see if u can see any blackish looking copper wire you my have non tinned wiring for your lights that may be corroded and not transferring the power thru the lines

a good time to upgrade as the other guys are saying go led