# Trailer lights trouble shooting?



## crittergitter (Jun 9, 2005)

Well, I finally picked up a nice starter boat. It's a 14 1/2 Spectrum with a Evinrude 9.9. Should be perfect for what I want to do. Anyway, there seems to be a problem with the trailer lights. I have running lights but no brake or blinkers. Anyone have this problem before? 

I've used a flatbed trailer for moving and it all works fine. So, the problem is not in my vehicle or flat wire. It's got to be in the trailer. So, am I going to have to re-wire the whole thing or just look for bad spots, a bad ground? I'm just looking to see if others have experienced this and trying to figure if I'm in for a real nightmare or a possible simple fix. Any input is greatly appreciated.


----------



## Kenlow1 (Jul 14, 2012)

Before re-wiring, check the sockets-may be corroded? I had the same problem. When I replaced the lights I switched to the sealed LED's-don't have to worry about water getting into lights and getting corroded.


----------



## multi species angler (Feb 20, 2006)

First thing I would do is check for corrosion on the trailer plug pins. And maybe even replace the trailer plug. Since it so easy to do and doesn't cost much.


----------



## bumpus (Jan 17, 2015)

Make sure each set of lights is individually grounded I had the same issue and it took care of it


----------



## Shad Rap (Nov 10, 2010)

It's the ground.


----------



## slimdaddy45 (Aug 27, 2007)

Trailer wiring is easy but start at the plug if there is a connection where the plug is wired on that's the next place then usually there's no more till you get to the lights use a test light easy fix


----------



## ya13ya03 (Sep 21, 2010)

I would just rewire the whole thing. Then you know it's right.


----------



## leeabu (Apr 10, 2004)

Most trailer lighting systems ground the through the trailer frame. If your trailer plug has the white wire from the plug bolted to the trailer frame, there may be corrosion or rust build up. Disconnect and clean it, reconnect and see if this solves your problem. If this does not solve your problem, you will see each light also will have a white wire bolted to the frame. Disconnect, clean and reattach these two connections. If you still have the problem, check the light bulbs. They contain two elements one for running lights and one for turn and brake. They could be corroded or the elements could be bad.


----------



## Shad Rap (Nov 10, 2010)

ya13ya03 said:


> I would just rewire the whole thing. Then you know it's right.


Good call.


----------



## Fishingisfun (Jul 19, 2012)

I agree with start checking for a good ground on each light to trailer it is the most common problem. Have a piece of wire and touch the metal on the outside of the trailer tail light and a good bare metal section on the trailer if it sparks your taillight to ground is not good. A good way to be sure your vehicle to trailer plug is operating is get an adapter with the led lamps in the socket it will enable you to interpret if the vehicle is sending the voltages to the trailer correctly.
Since the boat is new to you One item to check is be sure the bulbs in the sockets are the correct lamps. They will have two filaments one for running lamp and a second for brake. At times a wrong lamp replacement leaves you guessing. There are single filament bulbs that fit the sockets. Good luck. Let us know what you find.


----------



## G.lock (Apr 1, 2014)

99.9% of the time it's the ground.
I gave up grounding to the frame, I now run a ground wire from each light to the plug.
Actually I run a single wire back then tie each light to it.


----------



## crittergitter (Jun 9, 2005)

Thanks for the advice guys! I knew I'd get some good information here!!


----------



## backfar (Sep 24, 2014)

1st thing i would check is the bulbs to make sure they're both good.. 2nd thing i would check since im already at the bulbs is the sockets that the bulbs sit in, make sure they're not corroded..3rd would be to check with a test light the bulb sockets for power..if you cant tind a problem at the back i would go to the plug next...make sure your getting a GOOD ground, trailer lights should work when the trailer is OFF the ball when plugged in...good luck..


----------



## multi species angler (Feb 20, 2006)

He has running lights, doesn't that indicate he has a ground. Running lights aren't usually grounded separate.


----------



## Shad Rap (Nov 10, 2010)

multi species angler said:


> He has running lights, doesn't that indicate he has a ground. Running lights aren't usually grounded separate.


You can experience several things with a bad ground.


----------



## cincinnati (May 24, 2004)

How old is your trailer? Chasing odd light problems on my '88 Shorelandr & finally pulled the entire harness out of the frame. Found a couple small spots where the insulation had been worn to the copper, causing intermittent shorts & only occasionally blowing the fuse.

Turn signal AND brake lights should be on the green & yellow wires.


----------



## PromiseKeeper (Apr 14, 2004)

use a test light at the sockets. If you have power to there, its the bulb. Make sure you have a good ground for the test light. If the previous owner didn't disconnect the lights before launching the boat, the bulbs may have blown if they got wet.


----------



## Popspastime (Apr 1, 2014)

If you plan on keeping the rig for a long time don't cheap out.. re-wire the whole thing and buy 2 new lights.. So easy to do and your done. You'll be chasing that problem the whole time if you dont.


----------



## Smitty82 (Mar 13, 2011)

Not sure if this has been said yet but imo after you get it fixed its a good idea to use a little dielectric grease on all your connections.


----------



## bridgeman (Aug 26, 2010)

Harbor freight has LED's with a new harness... its easy to run the new wire. If you can afford to spend about 50 bucks you'll never have to worry about em for a long time.


----------



## Raider16 (Oct 19, 2016)

I personally would rewire, but is it possible that it might not have the proper dual filament bulbs? Might try replacement bulbs


----------



## sherman51 (Apr 12, 2011)

i'll through my 2 cents worth at you. what I would do is get new bulbs and why I had the old bulbs out I would use a test light and see if there is power going to the bulb. I would do if you don't have power is replace the wiring harness. but before doing any of that I would get some sand paper and clean both ends of the plug. its a little hard to clean the female plug. I tear off a small piece and roll it up then clean away. I've had dirty plugs give me nightmares. even though your running lights work it could be the ground. I had a trailer that the light was giving me problems using the trailer frame for the ground. I ran 2 dedicated ground wires from the lights to the plug and spliced in and it solved all my light problems.

the first thing I would do when I had a little money to spend id buy a set of led lights. 999 times out off 1000 if you have a problem with led lights its a dirty plug or a bad ground.

please let us know what and when you get it fixed.
sherman


----------



## crappiedude (Mar 12, 2006)

I agree with the guys who said go to LED's if you can afford it. It's so easy to just replace it all and start over with new. It's been the most trouble free lighting I've ever used.
With conventional bulbs it seems it's always something. I could count on something going wrong at least once a year and most of the times it was multiple times each year.
With LED's it's been trouble free and no need to unplug when launching. In the 7 years I've had LED's the only problem I had was a bolt came loose on a ground one time last year.


----------



## leeabu (Apr 10, 2004)

multi species angler said:


> He has running lights, doesn't that indicate he has a ground. Running lights aren't usually grounded separate.


The running light filaments are .48 amps each for a total of .96 amps for both running lights. His ground is capable of carrying about 1 amp with out opening up. The turn/brake light filaments are about 2.1 amps each. The poor ground that can carry the .98 running amp load, is not capable of carrying even one 2.1 amp turn/brake filament.


----------



## leeabu (Apr 10, 2004)

leeabu said:


> The running light filaments are .48 amps each for a total of .96 amps for both running lights. His ground is capable of carrying about 1 amp with out opening up. The turn/brake light filaments are about 2.1 amps each. The poor ground that can carry the .98 running amp load, is not capable of carrying even one 2.1 amp turn/brake filament.


 I also changed over to Harbor Freight LED lights years ago and have had ZERO issues since. Before I had normally multiple issues each year. I ran a separate ground wire to each light and thus have no frame ground. However the original post ask for help on how to troubleshoot the problem.


----------



## TRIPLE-J (Sep 18, 2006)

leeabu said:


> The running light filaments are .48 amps each for a total of .96 amps for both running lights. His ground is capable of carrying about 1 amp with out opening up. The turn/brake light filaments are about 2.1 amps each. The poor ground that can carry the .98 running amp load, is not capable of carrying even one 2.1 amp turn/brake filament.


then why do they use only one ground for the system?????
tail lights are usually powered by the brown wire to both sides...
right turn signal and brake is usually the green wire...
left turn and brake signal is usually the yellow wire...
ground is probably not the issue as this USUALLY stops all the lights in that housing to stop working and not just the turn/brake or running light...


----------



## fastwater (Apr 1, 2014)

TRIPLE-J said:


> *then why do they use only one ground for the system?????*
> tail lights are usually powered by the brown wire to both sides...
> right turn signal and brake is usually the green wire...
> left turn and brake signal is usually the yellow wire...
> ground is probably not the issue as this USUALLY stops all the lights in that housing to stop working and not just the turn/brake or running light...


So people will constantly have light issues as has been proven time and time again. 

Agree with all saying go to the 'submersible' LED lights(not just waterproof...there is a difference).

Then, in addition to wiring in your original ground wire that's coming back from the front of the trailer, run additional short ground wire at each light to trailer frame.


----------



## sherman51 (Apr 12, 2011)

I started checking my lights back in dec for a trip to fl. had running lights but turn lights was giving me fits. went to dedicated ground to each light and ran it up to the plug and spliced into ground wire on trailer problem solved. my old trailer just wouldn't carry enough ground to run brake or signal lights.
sherman


----------



## one3 (Dec 1, 2015)

crittergitter said:


> Well, I finally picked up a nice starter boat. It's a 14 1/2 Spectrum with a Evinrude 9.9. Should be perfect for what I want to do. Anyway, there seems to be a problem with the trailer lights. I have running lights but no brake or blinkers. Anyone have this problem before?
> 
> I've used a flatbed trailer for moving and it all works fine. So, the problem is not in my vehicle or flat wire. It's got to be in the trailer. So, am I going to have to re-wire the whole thing or just look for bad spots, a bad ground? I'm just looking to see if others have experienced this and trying to figure if I'm in for a real nightmare or a possible simple fix. Any input is greatly appreciated.


With the flat wireing plugs, I have found that a .22 cal bore brush fits into the holes of the plugs and will clean them up pretty well.


----------



## fastwater (Apr 1, 2014)

one3 said:


> With the flat wireing plugs, I have found that a .22 cal bore brush fits into the holes of the plugs and will clean them up pretty well.


Excellent...then some dielectric grease put into the holes and prongs will help to keep them clean.


----------



## Popspastime (Apr 1, 2014)

I always ground back to the tow vehicle in the harness, plug um in and they light and not thru the trailer. In the time this thread has been going a new harness, lights and even repacked bearings could have been performed, and have a trailer that will go a long time without problems.


----------



## TRIPLE-J (Sep 18, 2006)

fastwater said:


> So people will constantly have light issues as has been proven time and time again.
> LOL sooooooo true...
> 
> 
> ...


----------



## leeabu (Apr 10, 2004)

TRIPLE-J said:


> then why do they use only one ground for the system?????
> tail lights are usually powered by the brown wire to both sides...
> right turn signal and brake is usually the green wire...
> left turn and brake signal is usually the yellow wire...
> ground is probably not the issue as this USUALLY stops all the lights in that housing to stop working and not just the turn/brake or running light...


A good solid ground will pass all the current you need. A partial ground due to corrosion at a connection will not.


----------



## TRIPLE-J (Sep 18, 2006)

leeabu said:


> A good solid ground will pass all the current you need. A partial ground due to corrosion at a connection will not.


sorry
lol that was a sarcastic comment ... i know how a ground works lol
my post above explains how the trailer wiring works


----------



## Shad Rap (Nov 10, 2010)

Let us know how it works out...guaranteed it's a bad ground.


----------



## crittergitter (Jun 9, 2005)

Honestly, I'm in the middle of moving and haven't fooled with it much. I've had 2 other trailers hooked up (utility) and they worked great. So, It's got to be in boat trailer. I suspect the previous owner changed the bulbs with single filament, but I'll start with that once I get some time to fool with it. I will also clean up the connector. 

I'll post once I get to it with results.


----------



## triton175 (Feb 21, 2006)

Popspastime said:


> If you plan on keeping the rig for a long time don't cheap out.. re-wire the whole thing and buy 2 new lights.. So easy to do and your done. You'll be chasing that problem the whole time if you dont.


What he said.


----------



## Harry1959 (Mar 17, 2011)

I would check bulbs 1st. Especially since you lost both brake lights. On unsealed lights if you don’t unplug harness and back in the water it will blow the brake light/turn signal element every time. I do agree that bad grounds is the cause of most other issues.


----------



## crittergitter (Jun 9, 2005)

Bulbs are blown. Going to replace as it's the cheap route for now. I'll probably rewire the whole thing in the offseason with the water proof LED setup.


----------



## Popspastime (Apr 1, 2014)

Don't forget the Dielectric grease on them.


----------



## Harry1959 (Mar 17, 2011)

And don’t forget to unplug before you back into the water


----------



## fastwater (Apr 1, 2014)

crittergitter said:


> Bulbs are blown. Going to replace as it's the cheap route for now. I'll probably rewire the whole thing in the offseason with the water proof LED setup.





Popspastime said:


> Don't forget the Dielectric grease on them.


...and don't forget to unplug lights before launching.


----------



## fastwater (Apr 1, 2014)

^^^I think I heard an echo Harry1959.


----------



## Harry1959 (Mar 17, 2011)

Lol FW.


----------



## $diesel$ (Aug 3, 2018)

Probably old standard 1157 bulbs that we used to run in our old cars. HAVE TO unplug them, they won't take water when lit.


----------

