Trailering lighting problem

[Steve]

I have a problem thats annoying the heck out of me. None of the lights work on my trailer when just driving down the road. However, when I step on the brakes they all work. The blinkers work fine also. I checked all bulbs and they are all good. I checked all connections and they all seem good. The ground wire is attached and doing fine. Whats going on here?

[WackySenko]

Something similar happened to me. But all of the lights worked fine when we hooked the trailer up to my brother's truck.
I looked at my owner's manuel and found which fuse was for the trailer lights. Looked iat the fuse and, BINGO, blown fuse. Replaced and everything works. Good Luck

[Greg_Cornish]

Steve, is it grounded through the trailer wiring to the vehicle or just grounded to the trailer?

[ASD]

If it's just grounded to the trailer gress your ball

[szuloaga]

Sounds like you have the same problem I had just a week ago. I had a blown fuse in the hood of my truck and that was caused by a short in the trailer wiring AND one of the wires on the trailer was rigged incorrectly that was also part of the fuse problem. Hope this helps!

Steve

[ACRon]

I always suspect grounding issues. Especially if it is feeding through the brakes. Rigg a temporary ground wire to see if the problem goes away.

[Steve]

Ok, Im no expert on the grounding aspect of trailers, but I was thinking that may be the problem. I have the ground wire bolted into the trailer, and then of course the trailer hitch sits on the ball. I used to frequently take a grinder and remove all rust from the ball, however some scum bag stole my tools recently. What Ill do is just sand down the ball and see if that works. Somebody said something about rigging a makeshift ground wire. I assume what was meant by this is run a ground wire from the trailer to somewhere on my truck?

Wiring problems without a doubt are the most annoying.

[ASD]

Steve

Yes run a wire from the trailer to the fram of the truck.

[Tin Can]

Sounds like a ground issue, I go through this all the damn time with my old trailer.

[mark poulson]

Coat the ball with vaseline, and it should stop the rust, and make a good ground.

I hope there is a special He!! for thieves!

[Greg_Cornish]

Running a ground through your balls is always iffy at best. I don't see how greasing your balls would help. I had flickering lights on trailers that were grounded to the trailers. Since I have 3 boat and 1 trash hauling trailer I got tired of it and simplified things. I changed to all 2 inch balls and switched to a seven wire electrical coupler and grounded to the vehicle through the wiring harness. They all work great and I'm ready for any occasion.

[Greg_Cornish]

Coat the ball with vaseline, and it should stop the rust, and make a good ground.

I hope there is a special He!! for thieves!

Vaseline is also good for use on door knobs to keep the kids out of the room.

[Riplip]

Hey Greg, don't knock greasing your balls till you tried it...

[Greg_Cornish]

Hey Greg, don't knock greasing your balls till you tried it...

True, It'll sure make it slide in easier. Someone forgot to lift my lever and now everything in the coupler in bent out of shape.

[ASD]

Someone

[Steve]

Heres the thing I dont understand. If my ground wire is attached to the trailer and assuming the ground is good, why then do I have to also rely on the ground that goes through the ball into the truck? Ill be going out tonite so Ill guess Ill find out if its a ground problem. Last time out on my way home I had to ride my breaks everytime I saw a cop so my lights lit up. Fun stuff.

[Riplip]

Steve, like Greg I have changed my ground to the vehicle frame and never had another problem. I can't explain exactly why it works, but it's not a difficult or expensive mod.

Greg, if you had greased adequately, your lever would be very straight...

[Vernonn]

Steve,

It sounds like your ground wire on your plug is not grounded to the truck (could be caused by corrosion or pinched wire somewhere). With your truck lights on, and trailer plug connected, try jumping a wire from a bare spot on the body of the truck to the trailer frame. If it lights up, you have a ground wire disconnected or detached from the frame of the trailer.

All trailer plugs have a ground. The wire is usually white.
http://www.etrailer.com/faq-wiring.aspx

-vernon

[Greg_Cornish]

Heres the thing I dont understand. If my ground wire is attached to the trailer and assuming the ground is good, why then do I have to also rely on the ground that goes through the ball into the truck? Ill be going out tonite so Ill guess Ill find out if its a ground problem. Last time out on my way home I had to ride my breaks every time I saw a cop so my lights lit up. Fun stuff.

The coupler dances around on the ball and isn't screwed tight to the frame. Riding your brakes probably puts more stress between the ball and the coupler creating better contact.

Or, it could be a separate issue, the running (tail) lights and the brake lights are on a separate circuit (please correct me if I'm wrong) The Break lights and the signal lights are the same filament. If you signal left with the brakes off the left brake light flashes. If you signal left with the brakes on, both brake lights will come on, however, the current to the left brake light will be interrupted causing it to flash.

I'm starting to think the problem lies in either a break in the line to your tail lights or both tail light filaments are burned out from your description. Your ground could be fine.

[WackySenko]

Steve,
Did you check the tow vechile fuses yet? Look at the owners manuel.

[Tin Can]

If it was a fuse wouldn't the lights just not work at all?

[Greg_Cornish]

If it was a fuse wouldn't the lights just not work at all?

That would depend on the vehicle manufacturer I think.

[mark poulson]

I have a swing away tongue (to go with my greased ball) and my trailer lights won't work unless the tongue is extended and locked, and on the ball.

[Steve]

Ok, Im a dumb arse. The problem was a fuse. I broke rule of thumb number 1 which is to check the easiest fix first. And, my truck has two different fuses for a trailer, that explains why the lights wouldnt work when just driving but would work when I hit the brakes. Well, at least this was a good refresher course, and at least I know my wires and bulbs are good since I checked everything. Thanks everybody for the suggestions!

[Murph]

It's good that you found the blown fuses. But, there is still something "looming" that blew them in the first place. I would give the trailer another look-see.

[WackySenko]

The fuse could have blown due to the trailer plug not being tight into the truck plug and it was backed too far into the water.

[Sacto John]

Blinker and break lights run on the same wires (Brown-right hand and Yellow-left hand) in a 4 wire trailer system, while the running lights are on its own wire (Green) It is not uncommon for them to be on different fuses. My concern would also be why my fuse blew...if it is a reoccurring problem I would start looking for shorts/frayed wires.

[Murph]

Sacto John, I've always used the Brown wire as my Tail markers with the Yellow and Green being the Turn Signal and Brake lights. Yellow being the left and Green being the right. Not arguing, that's just the Standard that I use.

[Greg_Cornish]

Please let us know the answer when you find out.

[Tin Can]

Sacto John, I've always used the Brown wire as my Tail markers with the Yellow and Green being the Turn Signal and Brake lights. Yellow being the left and Green being the right. Not arguing, that's just the Standard that I use.

The link posted by Vernonn in this thread agrees with you.