Trailer lights freaking out!

[ajeckley]

The Problem:

Ok. I wanted to do a little work on my trailer today. What I thought (stupidly) was going to be a simple bulb replacement ended up being an all day mental meltdown complete with all manner of verbal embellishment. I believe that I have some type of short or a grounding issue. I know that my vehicle lights and trailer connection work fine. (I tested it with a meter and it also has LED's on the connector). Now, the signal lights are dim on one side of the trailer, the tailights only come on correctly on one of the brown leads, the other one is dim, but the brakelights work fine. Here is where it gets weird...There is some type of crossover happening that is making lights light up that do not have a wire connected to them! EX: When the LEFT turn signal was on, the RIGHT running light was lighting up.(Dim and erratic)

My Diagnosis:

A) The plug on the trailer end is shot and is causing erratic lighting and needs to be replaced. (Signal is jumping to other circuits).
B) The lights need ground wires run back the trailer instead of relying on a rusty old frame to provide adequate grounding.(Dim lights).

The Question:

Am I on the right track? I'm not used to working on 12V systems I'm hoping that I don't have a crack or stripped wire inside the frame that is shorting out. Does this type of problem sound familiar? Also, am I correct that the lights should be grounded through the bolt that holds them to the frame, so I can run my ground wires off them directly to my white wire on the truck?

Thanks,
AJE

 

[beermunk]

Re: Trailer lights freaking out!

The Problem:

Ok. I wanted to do a little work on my trailer today. What I thought (stupidly) was going to be a simple bulb replacement ended up being an all day mental meltdown complete with all manner of verbal embellishment. I believe that I have some type of short or a grounding issue. I know that my vehicle lights and trailer connection work fine. (I tested it with a meter and it also has LED's on the connector). Now, the signal lights are dim on one side of the trailer, the tailights only come on correctly on one of the brown leads, the other one is dim, but the brakelights work fine. Here is where it gets weird...There is some type of crossover happening that is making lights light up that do not have a wire connected to them! EX: When the LEFT turn signal was on, the RIGHT running light was lighting up.(Dim and erratic)

My Diagnosis:

A) The plug on the trailer end is shot and is causing erratic lighting and needs to be replaced. (Signal is jumping to other circuits).
B) The lights need ground wires run back the trailer instead of relying on a rusty old frame to provide adequate grounding.(Dim lights).

The Question:

Am I on the right track? I'm not used to working on 12V systems I'm hoping that I don't have a crack or stripped wire inside the frame that is shorting out. Does this type of problem sound familiar? Also, am I correct that the lights should be grounded through the bolt that holds them to the frame, so I can run my ground wires off them directly to my white wire on the truck?

Thanks,
AJE

You're on the absolute right track.

1) replace the 4 plug harness with some end-to-end connectors and shrink wrap.

that should take care of the issues. If not:

2) grind out a solid place for your ground wire on the trailer.

 

[spktho]

Re: Trailer lights freaking out!

If the lights worked well at one time, then it sounds like a grounding problem. The trailer should be ground right off of the plug. Check and re-ground that first.

 

[kamby]

Re: Trailer lights freaking out!

Sounds like ground issue. Make sure it is grounded properly on the trailer and is properly grounded on the truck as well. Even might go as far as removing the grounds clean up around them and re attache them with some dialectric grease for good measure.

If the wiring or the connectors on your 4 flat are turning grean its time to clean them or replace green (corroded) wires are bad.

On the lights themself depending on how they ground. if they ground through the mounting bolts remove them clean the rust up and remount, if they have a ground wire then remove wirre from frame clean and use dialectric grease. Another thing to check is the light sockets themselves since the sockets use the same for both break and turn it is possible they got corroded to and causing some wacky things to happen. One light on my trailer the socket got so bad i couldnt get the bulb out, it was like that when i bought it.

Also check any points where the wires connect to each other either scotchlocked or butt connectors etc. Make sure there clean and use diaelectric grease. and elec tape them. Do this on all wires, sometimes when teh connectors get corroded they do funny things, same with weak grounds.

with the amount of waters these trailers see im surprised at how long they last. (the wiring that is)


12v is similar to regular wiring, just not enough voltage to hurt. Now 120v low voltage wiring systems those can get confusing when you start getting in to the transformers/ballasters and what nots for those.

Good luck

 

[gostephen]

Re: Trailer lights freaking out!

clean all the grounds check all the wireing. if ur really unshure about the wireing go down to ur local auto parts store and buy a trailer lighting kit that has new wireing and new lights for about $35 or the led version (no more blown bulbs leds last for years) for about $50, and just replace everything.

 

[tashasdaddy]

Re: Trailer lights freaking out!

i solved my trailer light problems, years ago, when i added an extra wire, it is a single wire that goes to every ground, and then connects to the white wire on the harness. this way you do not have to worry about corrosion on the trailer, breaking the ground.

http://www.accessconnect.com/trailer_wiring_diagram.htm

 

[Radiac]

Re: Trailer lights freaking out!

go down to ur local auto parts store and buy a trailer lighting kit that has new wireing and new lights for about $35 or the led version (no more blown bulbs leds last for years) for about $50, and just replace everything.

This is what I recommend, also pull a dedicated ground wire down each side of the trailer and forget using the frame as the ground. This will solve your problems.

 

[tmcalavy]

Re: Trailer lights freaking out!

Good advice so far. Whenever I go through a trailer and find mystery light issues, I take a look at the wiring harness...if it shows any wear or appears suspicious I yank it out and re-install another new one. Can't beat the price and infinite peace of mind...no more worrying whether the latest fix/patch is still working,

 

[Moody Blue]

Re: Trailer lights freaking out!

Yep no doubt its a ground problem. With a bad or "partial" ground, the signal will run thru a different bulb filament to complete the circuit, thus you have dim lights (bulb filaments in series) and erratic possessed behavior.

I provide two ground points for each lamp. I pigtail the ground lead right at the lamp and connect a short lead right to chassis where the lamp mounts and run the other "dedicated" ground back to a common chassis gnd on the tongue. All my gnd points terminate at one location. Be sure to scrap or grind away any paint or corrosion under the ground connection points.

If you have a tilting type trailer, you MUST run a ground jumper (make it robust) between the tongue and the rear frame member of the trailer. You can't rely on the pivot point of the frame to provide a good ground connection to the rear frame of the trailer.

 

[Biggems]

Re: Trailer lights freaking out!

As the others have suggested, I too beleive it to be a ground problem. Some of the other folks on this thread may rememebr, I went through a HUGE ordeal to re-wire my trailer not too long ago. I had many similar problems and it all came down to a grounding issue.

First, you should have a seperate ground wire for each tail light. Ground each one of these to the mounting bracket for the light fixture. You can simply mount it under the bolt that holds the fixture there. Before you do that, scrape any paint or rust away untill you have fresh shinny metal.

Then you should also have a ground wire at the tongue of the trailer that comes out of the connector. Do NOT mount this wire on the coupler. Scrape paint/rust and drill a hole to mount that one there.

This is what I did and it solved all of my problems!

 

[stevenj]

Re: Trailer lights freaking out!

does the vehicle have an in line add on splitter? my ford ranger had one that
went bad and caused some strange happenings.

 

[reelfishin]

Re: Trailer lights freaking out!

On any of my trailers with either tilt or those that bolt together, I add a jumper ground from the tongue to the frame rails, or simply run the white wire directly back to the main frame.
Use star washers on all ground connections and to keep out corrosion, you can paint the ground connection when your done.

 

[capt sam]

Re: Trailer lights freaking out!

I just spent today completely rewiring my trailer. The previous owner thought it'd be awesome to wire the trailer with extension cords taped to a butchered wiring harness. It just started shorting out and I wasn't about to chase the problems.....I should have taken pics, it was a real work of art.

 

[kamby]

Re: Trailer lights freaking out!

Lots of good advice. And with all the water these trailers see, they can rust out pretty good. Tilt trailers are even worse cause they rely on the pivot point to ground. Extension actually do make good trailer wiring, there 3 wires in them already. Plus with the extra insulation makes them more durable. Ive seen them used on car trailers with all the lights and what not, they usually connect into a 6 or 7 way plug.

Not sure what lights you have but you can run a wire from the mounting bolts to the ground point as well. Thats one of the main things i dont like about the lights that get ground through the posts. If they get rusty or the trailer does u gotta clean em and check for corrosion which can cause shorting out.

You got lots of good things to do to help get a good ground and this should solve your issue.

Had someone ask me to help them put a new starter on there lawn mower, it was clicking at the solenoid but nothing from the starter, they even went as far as purchasing a new starter and solenoid. So i tested the system was getting 12v to the solenoid and 12 volt to the starter, so i took the starter off the block and low and be hold the legs were rusted on the starter not getting a ground cleaned them off attached some jumper cables to teh starter and battery and she spun good and fast. hooked it back to the lawn mower with clean legs and started right up.

 

[ajeckley]

Re: Trailer lights freaking out!

Wow! Thanks so much for all of the good advice! I've got this thing pretty well resolved. Had the boat on the water this afternoon and even able to reel in a couple bass, even in our still freezing Pennsylvania water. As for as the lights I wired up a new harness and used the 3m shrink wrap crimp connections which work AWESOME and I can't imagine ever using anything else, as well as replacing all of the other connections at the back of the trailer. I also cleaned up all of the sockets, replaced all of the bulbs, and ran a ground wire directly to the lights. I used some 12/2 romex tied to the mounting bolts as I have an abundance of it around. I figured it should be fine since it's just a ground. I ran a jumper off it to ground the trailer. In any case, it works perfect, however as stevenj described I have an issue with the truck too. It sent a signal back to the truck through the ground so I've got to replace the converter on my pickup tomorrow. I realized this because it read a negative voltage when I tested the tail lights. Thanks a lot u-haul. I had this thing replaced only 2 years ago. Fortunately my Dad was gracious enough to do the towing today.

AJE