Trailer wiring problem/question

[icefisherman]

I've discovered last night one(left) brake light on my trailer doesn't work. The right one is working fine. All the other lights - running, turn signal are working fine also. Bulb is fine, I've changed the right with the left bulb - same problem.

 

My trailer is from the US and has not 4 but 6 wires coming out of the plug - 3 to the right (green, brown, white) and three to the left (yellow, brown, white).

 

It seems the yellow wire on the left carries the turn signal AND (?!?) the brake signal.

My neighbor came look at it could not figure it out and he is playing with cars for hobby and know somewhat about wiring.

My other neighbor came, he is electrician, also could not figure it out.

 

It doesn't make much sense that one brake light is working and the other is not and the bulb is OK.

Can anyone come up with solution how to resolve this?

Don't want to replace all the wiring again. Just did it on my old boat trailer before selling it last year.

I'd like to avoid the exercise if I could.

 

Thank you.

 

 

Chers,

Ice Fisherman

[Snowball]

Here is a URL to some wiring diagrams that may help you out:

 

http://www.etrailer.com/faq_wiring.aspx

 

Regards,

Snowball

[Terry]

white is ground

yellow is left stop and turn

brown is right stop and turn

green is tail lights

 

if it is not bulb or connection problems

then it has to be ground

[Dondorfish]

white is ground

yellow is left stop and turn

brown is right stop and turn

green is tail lights

 

if it is not bulb or connection problems

then it has to be ground

 

 

My guess is that Terry is correct. Sounds like a ground problem on the individual light. Remove the light and clean up the connection where the light is grounded to the trailer. - just my 2 cents.

 

 

Don

 

[icefisherman]

Terry sure is correct on what color is what.

But now.....if it is ground problem....why would the right brake light working and the left does not?

And also....same bulb also serves as running light and turn signal - both those are working fine....so how come the same left ball works fine when turn signal and the running lights are on but doesn't work when I press the brake pedal?!?

 

Cheers,

Ice Fisherman

[Gerritt]

I know I had the same issue. I was pulling my hair out as the trailer was brand new... turns out it was the plug on my truck that was the culprit.. on of the wires had some of the insulation missing.... yup corroded to the point that it broke..

 

 

Just pointing this out as the trailer is not always the issue..

 

G

Edited April 18, 2008 by Gerritt

[POLLIWOGG]

brown is on both sides makes it tail lights, doesn't it?

[Big Cliff]

Well, if you are close to Lindsay and want to bring it over I can fix it for you.

[Bernie]

Brown is tail lights. Green is right turn and stop. Yellow is left turn and stop.

Some of the newer pickup trucks have separate fuses for trailer lights. Verify your vehicle trailer power output first.

Then verify ground is working and is grounding to trailer. this step a lot of guys miss and it can really mess you up.

Edited April 18, 2008 by Bernie

[wallyboss]

A bad ground can make a grown man cry. I would say that 95% of light issues on trailers are bad grounds. If there is a problem that nobody can figure out it will turn out to be a bad ground somewhere.

[icefisherman]

Well, if you are close to Lindsay and want to bring it over I can fix it for you.

 

 

Appreciate your kind offer Clif but I am in Georgetown.

May have to use the service of someone who knows those things very well though and is close to me as I don't know what else I can do to fix it....spent two days ask three other people.....nothing....

 

 

Cheers,

Ice Fisherman

[Terry]

sometimes to find a ground it will back feed thought the other light, so one will work and one will not or sometimes the second one will be really dim

 

so test, run a wire from ground on the truck to ground on the light that's not working you might need to sand the metal to get a good connection

[Gerritt]

Should be fairly simple if you have a volt metre.. apply voltage to the various pins on the trailers plug...

 

attach volt metre to the light in question.. this should give you an answer as to what wire had the issue

 

volt metre can be had cheap... I am sure your electrician friend has one....

 

remove the bulbs however..

 

Dont see why this wont work...

 

G

[icefisherman]

Brown is tail lights. Green is right turn and stop. Yellow is left turn and stop.

 

Precisely Bernie....and since the left side is the problem one, the yellow wire is the one in question as it does turn and stop for the elft.

The strange thing is, the turn works fine(while using the SAME yellow wire), and both bulb elements inside the bulb work fine when turn signal or running lights are on.......just that for some reason pushing the brake pedal does NOT send electric signal to the bulb....the same bulb that works otherwise with turn signal and running lights, over the same Yellow wire that carries fine the turn signal but does not want to carry the brake signal..........drives me CREASYYYYYYYY!!!!

 

Cheers,

Ice Fisherman

[icefisherman]

sometimes to find a ground it will back feed thought the other light, so one will work and one will not or sometimes the second one will be really dim

 

so test, run a wire from ground on the truck to ground on the light that's not working you might need to sand the metal to get a good connection

 

 

But Terry,

if the grouns is the problem, why do the running light and turn signal on the SAME LEFT side work fine?

 

Gerrit,

my electrician friend spent 1 hour this afternnon with the volt meter in hand and couldn't figure it out....

 

Cheers,

Ice Fisherman

Edited April 18, 2008 by icefisherman

[Bernie]

So is there a brake light signal coming out of the truck? Your problem may lie there. Still a possible fuse. What kind of vehicle?

[muskymike]

I know I had the same issue. I was pulling my hair out as the trailer was brand new... turns out it was the plug on my truck that was the culprit.. on of the wires had some of the insulation missing.... yup corroded to the point that it broke..

Just pointing this out as the trailer is not always the issue..

 

G

 

I am in the same boat as G

 

I rewired the trailer 2 weeks ago, turns out it was a wire on my harness on the truck side.

 

look at that before you "start to look like G"

[icefisherman]

So is there a brake light signal coming out of the truck? Your problem may lie there. Still a possible fuse. What kind of vehicle?

 

Nissan Pathfinder.

Brake signal is fine out of the truck, fine on the right side as well.

 

Cheers,

Ice Fisherman

[Bernie]

Check to verify the left signal housing is grounded. I think you will find your problem there.

Cant think of any other possibility.

To check run a wire from the trailer ground to the ground around the bulb. That is if it is an 1157 style bulb. If it isnt try to trace the ground path and touch the wire to it at the bulb.

Edited April 18, 2008 by Bernie

[Terry]

do nissans run a different wiring system then American built trucks....seems I remember installing an adapter to make a nissan work with a regular wiring harness

but that was many years ago

[Dondorfish]

May sound stupid - but have you tried cleaning the contact inside the bulb socket - could be corroded. If clean - take a 12 volt tester ( the one with the light ) and have someone step on the breaks - light should come on. If no power at the contact - check the wire outside the socket to see if there is power there. Trace it back till you find power and that should be where the problem lies. I have had wires in the past with a break inside the wire and no visible sign of damage.

 

Don

 

[Bernie]

Terry, I assumed he already had that done if it was necessary. Seeing as he does have output at the truck technically it should work the trailer if trailer is working correct. The signal works therefore it proves the left power circuit. When applying brake it therefore cannot get ground through the opposite filament. Hence the thought on bad ground at the tailight itself.

[icefisherman]

Guys do you want me to go and take pictures of the left plastic plate holding all the wires/bulbs at the back of the trailer?

If it helps you I can post the picture.

 

Cheers,

Ice Fisherman

[Bernie]

Ya, sure if you can. Still almost convinced its a bad ground.

[icefisherman]

OK hope this helps:

 

This is the trailer connector.

 

Here is the plastic insert/plate holding all the bulb/wires:

This is the left side

 

 

 

 

Cheers,

Ice Fisherman