Trailer Wiring Help

[Meely]

Hello gang!

Hoping I could get some help with the wiring/lights on a small boat trailer.

 

I was given a small boat trailer that I plan to use to haul a small 12 ft

aluminum. The trailer was totally rewired with new LED lights.

Hooked the trailer to a newer vehicle and all lighting worked.

 

Hooked the trailer to my vehicle 2003 chevy venture .....( i know... a relic but it still runs fine).

 

When hooked to my van :

1) the LED running lights go very dim

2) the passenger light will not work when the full headlights are on

3) no passenger brake lights when full lights are on

 

I checked the current plug (flat 3 plus 1) and all 3 slots lit the tester up and the ground is connected.

 

I read that multi-bulb vehicles need a small converter box to get the lights working. Heres the kicker, I removed the small panel at the back

of the van and noticed that I already have a converter box feeding the current wiring but as I said.... not all lighting configurations work.

 

Would appreciate any and all help.

 

Tnx Meely

[porkpie]

Clean the inside of all harness contact points with a nail or small screwdriver or the like. After trailer harnesses sit for a while they develop a green corrosion that can effect contact. After you've cleaned them up as best as possible then put some dialectic grease on both contact points (Canadian tire automotive section). If that doesn't fix your issue, pull all wiring and start over LOL. Trailer wiring is a PITA! You may check your fuses as well. Unlikely that is the problem but you may as well have a look. If your using a converter box you probably don't have a dedicated trailer stop/turn fuse. It's also possible that your converter is pooched, but more likely that you've got a bare wire somewhere or a break in the wire. So check all visible wiring especially near pinch points in the tow vehicle. Good luck, I hate trailer wiring!

[OhioFisherman]

Make sure you have a good ground? A rusty trailer hitch ball or rusty parts in the hitch itself can cause all kinds of problems?

[Sinker]

Ground the light fixtures to the trailer.

 

S.

[landry]

Almost every light problem I have had has been a ground issue. Clean and reattach the ground connection points and I bet it fixes it.

My buddies escort has some wierd issues with his trailer and truck lights though so who knows.

[landry]

Not escort. Escape.

[Garnet]

On your trailer harness. Do you have a white wire not attached. If you do extend wire to trailer tough drill a hole, self tapping screw works good, shine up area and attach.

[Fisherman]

Time to trade in the GM. If your vehicle lights work without trailer attached then the vehicle is fine. If they malfunction with the trailer attached, go back to whom gave you the trailer and ask for some Tylenol and explain you have a headache and are ready to inflict pain on them. Go to PA, get a wiring kit, read the instructions or have a competent person install it. In addition, run a dedicated WHITE ground wire from the trailer hitch end to each light socket.

Edited June 22, 2017 by Fisherman

[Meely]

Thanks for all the info so far.

As I mentioned , the trailer has a brand new LED wiring kit installed and everything works fine when attached to my buddys newer F150.

 

I only encounter issues when attached to my van so I am going to assume the issue has to do with the current tow wiring set up???

[porkpie]

It could, and I've chased issues like that in the past in my suv. Mine was related to a short from a bare wire. When you say hooked up, in sure you mean attached to the ball as well not just the wiring hooked up. If the trailer isn't actually hooked up to the vehicle some lights will operate but it won't ground out properly and you will experience intermittent light issues. Ground issues are very common, but it's not the only cause especially with older wiring harnesses in vehicles. If you've cleaned all contacts, checked all grounds, hooked up properly and have a trailer with known good wiring, then start looking for bad wiring on the tow vehicle.

Edited June 22, 2017 by porkpie

[KLINKER]

If it is a tilt trailer you might need to run a short ground wire from the tongue to the frame .

[jimmer]

Definitely check the grounding system. However, I had a vehicle that the converter seemed to break down every year or two, so that might be your problem.

[DRIFTER_016]

​Definitely an issue on your vehicle.

Check the ground wire (White) for a good connection.

Check the plug to make sure it's in good shape and not corroded.

Check all connections and make sure they are not corroded.

 

Lastly check the output of the converter to see if it's functional.

Have had one or two in the past do strange things and replacing it fixed the issues.

 

 

FYI, the trailer does not need to be connected to the ball for it to ground.

That is what the white wire is for.

 

Best practice when wiring up a trailer is to run your ground to the lights and not depend on grounding to the trailer frame.

Good sealed connections will not corrode and give you lighting issues.

I use the heat shrinkable butt connectors with the hot glue in them to make a water tight seal on all of my connections.

[porkpie]

Drifter, I agree with all that you have posted, but have definately seen more than one trailer that lights would not operate correctly when truck wasn't connected to ball. YMMV

[DRIFTER_016]

Drifter, I agree with all that you have posted, but have definately seen more than one trailer that lights would not operate correctly when truck wasn't connected to ball. YMMV

 

And the reason is a bad/missing ground connection (the white wire).

[Sinker]

 

And the reason is a bad/missing ground connection (the white wire).

Yup, usually its the light fixture itself thats not grounded properly.

 

I solder all my connections and shrink wrap. I haven't had an issue with lights for a long time, but lately I have one light socket that my bulb doesn't like to connect properly in.

 

Time to install the new LED kit I guess.

 

S.

[aplumma]

To test the ground just put a booster cable from the trailer to a frame bolt. Scuff them around for a good connection and go from there. using a grounded test light check car truck in each socket and make sure the wiring is correct in the vehicle.

 

 

Art

[dave524]

Definitely check the grounding system. However, I had a vehicle that the converter seemed to break down every year or two, so that might be your problem.

 

 

My landscape trailer lost the brake and direction signal on the drivers side, cleaned all connections and grounds still nada. Multimeter at the vehicle flat plug showed no current on one of the plugs with the other probe grounded to the ball, tail lights and right signal showed current on the others, converter is toasted I guess.