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Troubles with trailer lights

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Manitoba_Rancher

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I was wondering if anyone would have any suggestions on some problems we are having with the lights on our stock trailer. I ve changed the electrical plug and the brake lights and signal lights still wont work. The running lights all come on when you turn the lights on but no brake lights or signal lights. Where should I start to look? :???:
 
Don't ask me,didn't have lights tried EVERYTHING.... last week haulin cows home from pasture lights came on :???: :???:
 
MR.....just like electric fencing most problems go back to proper grounding! Check the main trailer ground as well as the individual lights for corrosion and/or rust.It doesn't take much to disrupt the circuit! We have an old 45' Freuhauf hi-boy we haul bales with.....last year all the lights quit except for a couple of clearance lights......thot I'd have to rewire the whole thing......cleaned the ground up and I had a complete set of lights!!! Call it magic or preventive maintenance....it usually works!
 
The left signal light and brake light wasn't working on a trailer last week. I pulled in to have a mechanic examine the problem, and all he did was to spread the prongs a bit for a better connection where the chord plugs into the pickup bumper. Now the trailer lights work like a charm.
 
90% of problems will be in the plug make sure there is a good ground also trailer's ground through the ball.If you have a fold over ball of any type these make for poor ground's find the ground wire for the trailer and ground it to the trailer itself.Also alot of newer trucks are pre wired the factory connections under the truck sometimes corrode you will need to cut them out and hard wire them.
 
Trailer light problems can drive you crazy! :mad:

I have found that almost EVERY problem with trailer lights can ultimately be traced back to:
A) Poor grounding and/or connections.
B) Improper plug connections ( prongs, mud, rust, wiring, insulation)
C) Broken wiring.
D) Aluminum wires can be a problem after a few years of age.

It is almost a way of life that if you have lights of any kind on trailers you are going to, at some time, have trouble with them.
And you just have to patiently ( :shock: ) re-trace and follow - re-trace and follow, and a few 'few-letter' words won't help you find the problem, but it usually makes you feel better!

DOC HARRIS
 
Check your fuses on the truck. Mine was blowing truck fuses and like some of the others said, it traced back to the ground.
But an intermittent ground may blow the trailer stop and turn fuse. Then when the ground is working the other lights work.
 
I can't believe the lame answers ...check grounds, check plugs...sheesh. it is so obvious. Your truck's electrical system is going to fail very soon the first sign of trouble is trailer lights that don't work right. The next thing that will happen is the wheels will fall off the trailer. Very common right after the lights go.

The solution is easy. Go to your favorite dealership and plunk down 50K plus on a nice shiny 2005 or even 2006 model if you want to get fancy schmancy. Then take the truck to a hitch place, lay out $500-$1000 on the appropriate hitch/wiring harness, then head straight to the trailer place and kiss another $10-20 K good bye. The lights will work fine for about a year or two depending on how many cows chew on them. :wink:




Actually the advice about the ground is bang on.
 
Try replacing the FLASHER Plug in the truck. Sounds like a similar thing that was happening with my truck/trailer. Don't by the cheap ones, try the plugs meant for 10+ lights. it only cost me about $10 at the local TruValue.

Good Luck............
 
Trailer lights have been added to the cirriculum in hell.


When you pass on to the next world, and you have not achieved any rights to enter the pearly gates, you will be assigned a special place in hell.

You will be given 500 2-cycle engines, some will be in chainsaws, weekwhackers, lawnmowers, etc. None of these will run. You will be give a pair of common pliers and a couple of worn out screwdrivers and a lot of contaminated gasoline.

It will be your job to get all of those 2-cycle engines running and keep them running for eternity. If you are successful, you will put them on an old rusty gooseneck trailer with poor wiring. If you can get everything working at once, including the lights and brakes, you will get one more chance at the pearly gates.
 
I've gotta couple of pups that think the trailer plug hangin down from under the bumper is a chew toy.....in less than a week. they chewed off 3 plugs on three different vehicles.
 
Trailer lites are easy to get working,if you have a volt meter,your half way there if the running lites are working,and have proven you do not have a bad ground.
I am sure you got em fixed by now,but for trailer wiring problems keep a cheap meter on hand ,and when you start to use it test it first,by placing the leads on a good battery.
When I am tracing wiring on a trailer,one trick is to use a straight pin or needle to penetrate the wire jacket and test to ground.
On the flashers ,just turn on your flasher and test each wire for pulsating voltage to ground,do your brakes the same ,have some one depress the pedal as you test..................good luck
 
I know that salt will eat a vehicle up pretty quick,I have a neighbor that bought a Dodge Pickup same time that I did,and was showing it to me couple days ago,he goes down to the coast fishing often and doesnt wash his truck off when he gets back,It has all the front end rusted through and lots of body rust,where mine doesnt have a bit of rust.......good luck You are gonna have your hands full this winter,if you are gonna try and feed 400 head of cattle ?
 
Got the lights working again. After a few hours of checking things out I headed into the ford dealership and it was a faulty fuse, that you could not see with the naked eye. They have a little fault finder they hook directly into the plug for the trailer and they can tell right away.
 
My Dad says "Ground"

Run a Short wire from the truck to the Trailer to ground it and see if it works - - He says 80% of all trailer Light troubles are the ground.
 
I guess you have it fixed for now. I was going to sudgest you hook up to another truck first and decide if it is the truck or trailer.

If you don't have another viehicle to hook it up to then a good test light is the next best thing. If you have current standard hook up ( RV round 7 ) when you look at the connector we will assume it looks like a clock. with the six main connections at 1 - - - 3 - - -5 - -- 7 - - - 9 and 11 o'clock. you are testing for the proper connections.

1 oclock is often left blank but should have power whenever the ignition is on to recharge the break away battery

3 should be the right turn signal ( also brake light)

5 is the ground - - -very important

7 trailer brakes

9 left turn signal ( also brake light)

11 tail lights

the center is often used for trailer dome lights or back up lights

If everything checks out fine it is time to test the trailer.

For this purpose a small trickle charger works great.

Attach a small piece of copper wire to each lead and insert the ground into the ground connection ( remember the connections are a mirror image ) and then insert the hot lead into each problem connection to power the proper circuit so that you can then start with the bulb sockets and work back to the plug to locate and correct problems.

In areas with salt problems I would not pierce the insoluation as it can come back six months to a year later as a corrosion problem. I use dilectric grease on all bulbs and sockets and don't forget "liquid tape" to cover the electrical tape - - - this will help stop the corrosion.

I hope this helps but it is hard to explain without a better visual aid
 

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