Boat light wiring help

[Pete112288]

So I have done a decent amount of wiring in houses and in my boat and such in the past.
However I am having an issue right now I just cannot figure out.
I am trying to wire the red & green nav lights at the bow of my boat. 15ft boat, battery in the rear, switch mounted on the side console about halfway up the boat, and the lights up front. The lights are new little 3inch LED strip lights that take very little power.
The first switch I wired up was an old one thats been bouncing around a box in the garage. 12v 30amp switch. I hooked it up with the switch wired to the neutral wire.
Turned it on and only one of the lights came on and it was super dim. I figured that old switch may have been damaged or something.
So I got a new, marine rocker switch 12v 20amp. It does the same thing the first switch does.
However, if I remove the switch entirely and just wire it straight through, I hook it to the battery and both lights come on and are brilliantly bright.
I then tried wiring a light switch for the house into it. With that switch it also works flawlessly. But if I wire one of the switches intended for it, only one light comes on and its super dim.
Any ideas why it works so well otherwise but not well with the switches designed for this use?
Because its the wire I had available it is 14 gauge THHN wire running from the battery to the switch, and switch to the lights.
Thank ya

[Griiz]

I wonder if you have the bad luck of two bad switches.

[Caseknife]

Polarity makes a difference with LED lights.  Don't need a lot of amperage, but they do need full voltage.

[CP]

My guess is that the 20A and 30A switches are not seeing enough current to keep the contacts clean as the LEDs pull well under an amp.  Dirty contacts = voltage drop.

Maybe try a switch that is designed for LEDs.

[Bearomatic180gr]

Sounds like you have a bad ground. And I’m guessing it’s with the switch. The wire gauge should not be the issue. 14 gauge is not that thin honestly for a led light strip. Maybe an additional ground from the switch to the negative battery post is in store. Or better yet just ground the switch directly to the negative post on your battery. Make sure your wires are crimped well, do tug tests on your wiring.


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[millerwheeler]

Bad ground , bad crimp . I’m not a real
Fan of using any crimps i solder and water proof any connection especially in off-road and marine applications. No need for that switch to be rated that high for those led strips either led draw very little power in that form.

[MeepDog]

Post pictures.

Just to be clear, the wires for the LED strips need to be joined together so that the two lights are in parallel. I hope you arent putting each lights wire on a different terminal of the switch. If the switch has 3 terminals on it, you have a 3 pole switch and you should only be using 2 of the 3 for what trying to do.

Soldered connections are your best bet for joining to those little led strip wires. If you think it should be on, give your connections a wiggle with your hand and if the light blinks you have a loose connection.

[Pete112288]

Thank everyone for the help. Turns out I had it all messed up. I looked at the picture and ignored the words in the diagram for the switch. The color of the wire in the diagram was red for negative and blue for positive. I was so used to red being the positive side that I overlooked it and wired it incorrectly. Unfortunately what finally came of it was a situation that completely fried the negative/neutral wire in my cable for the electric start on the outboard. Ran the couple LED lights and depthfinder off of the cranking battery with the big motor. I had got all the lights to work, and was able to run the motor at home in a bucket. But I never tested it out with both circuits connected at the same time to the battery. So I had positive and negatives all messed up on the little circuit and the wiring for the motor when I got it was also grounded to the aluminum of the boat itself (which I heard since then is not how its supposed to be). So somewhere along the line things got crossed and friend the negative wire for the motor cable. Luckily the in line fuse in the motor saved the wiring within the motor itself. But its a 1990 Johnson motor and was a giant and expensive pain to find a new cable that was long enough and had the correct old style plug to match the plug on the motor. I suppose I could have hard wired the cable to the motor and found a cheaper source for the cable, but I dont want to have to rewire anytime I want or need to take the motor off.
It ended what was supposed to be the maiden voyage of the new to me boat before it got off the trailer but some lessons get learned the hard way I suppose.

[Encore 280]

Hopefully you used marine grade wire. If not, regular 14ga wire won't last long around saltwater and you'll end up with more problems. 

[Happy Gilmore]

Did you use only yellow wire nuts?

[Pete112288]

So I have the motor all fixed up with new cable, ran to the side console controls and everything is working fine motor wise. I really want to run my nav lights and depth finder off the starter battery but am nervous now due to what happened before. Do I need a fuse along the run for the lights and depth finder? I have a roll of 16 gauge marine wire to do it since I have so few electronics and the lights are all small LED.
With wiring things correctly this time, I should be able to just put the terminals of the lights/depthfinder circuit and the terminals for the kotor right on the battery posts together right?

[CP]

Yes, to both questions.

[Ridgeratt]

Cheap insurance to fuse every load.

[Bearomatic180gr]

In line “fuse holder” and 20 amp “maxi fuse” obtain at napa. Do not use a mini fuse. Buy some die electric grease and slather on all the terminals and battery post. Use zip ties to tie wiring up tight eliminating rubbing or shorting to ground. Not too tight keeping in mind everything is susceptible to a little “flex”.

[Pete112288]

A 20 amp fuse isn't too big for just the lights and depthfinder circuit?