LED NAV light not working

[Cool Hand Luke]

I’m replacing my starboard NAV LED light but it’s not working. For some reason, i still get 12V-ish on the line. I switched the red and green and the green works on the port side but the red doesn’t work on the starboard side. This tells me that it’s not the light. Any thoughts?

Can I split the 12V line that’s going to the port side and connect both lights to it? I’m at a loss. This is such a stupid issue and should be simple. I understand if the voltmeter shows 0V. But it doesn’t. And the light works when a 9V battery is connected.

Any input will be greatly appreciated before I rip all my hair out







(Green working on a temp 9V connected)

[Bleemus]

Bet if you replace those butt connectors with heat shrink ones you will find your problem in the connector.

You can have twelve volts but if there is enough corrosion in the connector you will have too much resistance to power the bulb.

[Reefmagnet]

^^ Wot he said

[ramblinrod]

Originally Posted by Cool Hand Luke

I’m replacing my starboard NAV LED light but it’s not working. For some reason, i still get 12V-ish on the line. I switched the red and green and the green works on the port side but the red doesn’t work on the starboard side. This tells me that it’s not the light. Any thoughts?

Can I split the 12V line that’s going to the port side and connect both lights to it? I’m at a loss. This is such a stupid issue and should be simple. I understand if the voltmeter shows 0V. But it doesn’t. And the light works when a 9V battery is connected.

Any input will be greatly appreciated before I rip all my hair out

Attachment 172956

Attachment 172957

Attachment 172958

(Green working on a temp 9V connected)

Q1: Why is there a separate voltage supply to each light?

Normally, there is one 2 conductor cable running forward from the DC panel switch or breaker marked "Running Lights" to the bow lights, where it is then split between the two (in parallel).

Q2: What is the voltage measured at the light terminals with a load connected?

(If it is 12ish open circuit, and 0ish loaded, you have a high impedance somewhere in the supply to the load.)

Q3: If the answer to Q2 is 0ish loaded, what is the voltage across the butt connector in that circuit. (If it is 12ish loaded, that is the problem, if 0ish the problem is elsewhere.)

Note that you may want to fix the leak on that deck mounting fastener in the upper left corner of the photo.

[SV Bacchus]

This is a simple test but may be the issue: Some LED lights are positive and negative specific. In other words, if you have the hot going to the negative lead, the light won't work. Try switching the the two leads around.

Good luck!

[foufou]

Are you certain the polarity is correct?

[ZULU40]

Originally Posted by SV Bacchus

This is a simple test but may be the issue: Some LED lights are positive and negative specific. In other words, if you have the hot going to the negative lead, the light won't work. Try switching the the two leads around.

Good luck!

Yes, generally older form LED's but voltage polarity specific is still quite common. You must make sure your polarity is correct + to +

[roverhi]

Don't rely on the color of wire from the light to determine polarity. Had a bicolor bow light with red as ground and black as hot. wasted several hours trouble shooting before it occurred to me to switch wires around.

[hellosailor]

Actually all LEDs are polarity sensitive. Hook 'em up in reverse and they either blow or don't light up. The better "LED bulbs" have additional components built into them to work around that problem--but the additional components add cost and waste a tiny bit more power.

[OldGreyB]

1) As a thought process, before you replaced the LED- were both sides already working with the old lights, or was that the motivator to change out to new LEDS? As if the one side was not previously working, then a bad electrical wiring connection could have been the original route cause. The fact that neither work on the STB side is an indication you have a wiring issue, even with "12sh Volts".

2) The digital voltmeter can read a voltage, but a high resistance joint on the feed side or ground connection will not allow sufficient current to flow to light the LED. A 12V 5 watt standard auto light with a two wires is always a good test tool to have in your toolbox. It provides a good load to check at all points of the wiring when fronted with this sort of issue. Your LED test has proven that to you already!

3) Not sure if you have separate breaker cirucits for each side , but if you do, , try one of the LED's ( or filament light as per above) directly on downstream of the PRT breaker and to a good local ground. If it lights = good ground, so now try on the STB breaker, if it does not work - breaker issue. If the check light does work directly at the breakers check the existing connections at the breaker panel and very importantly at the return wiring grounding points for corrosion.

4) As per Ramblinrod post , normally there is one running light circuit going forward, if that is the case then you need to locate the junction where the PRT and STB split, as that is probably where the high resistance joint is for the STB side.

5) Check polarity of the connections @ the LED for all the reasons already stated by others. You can use a good local ground to check if the ground path is "high" while doing this too.

6) I concur, ditch those cheap auto butt connectors even thought they look newly installed. Use only crimps with the heat shrink and shrink them down when all has checked out. Then you'll never have to go back to these connections.

7) To answer your original question, yes you could join the STB and PRT LED's together on one circuit, (that is common installation as per 4 above). Your installation may have separate wires running PRT and STB from the same breaker, so check carefully both sets of connections at the Breaker and grounds.

8) If you go to the basics above, then you should be able to find the issue. When you resolve it - post back the resolution so others can learn.

[SV Bacchus]

Originally Posted by OldGreyB

8) If you go to the basics above, then you should be able to find the issue. When you resolve it - post back the resolution so others can learn.

Yes, please do!