Good day guys.
The lights of my trailer seem to be dimming with time. I checked and all connections are OK, I have used contact cleanner for the plugs, etc. but this is not resolving the problem. Do you have any experince with this ?. Your advise will be very much appreciated. Thanks / Rafael

Question for you, is your trailer rusted at all? this will cause a current drain and the lights will dim with that. How is the ground connection to the trailer and your tow vehical?

I have run a ground wire to all the lights on my trailer to ensure that I have a good connection all the way around, and i currently dont have a dimming problem.

The Skier
1973 H16

get the newer LED based trailer lights.

They are pretty pricey as trailer lights go, but they are sealed, and the corrosion that plagues normal trailer lights isn't an issue with them.

Check the ground connection at the trailer. It is usually grounded near the tounge, and this connection often becomes rusted or broken off. The lights usually ground by their mounting bolt. IT gets rusty rusty too. I ran a extra wire for ground all the way to the light mounting stud to eliminate a similar problem with mine. Maybe try new bulbs as well.

I agree it sounds like the ground. Usually the ground wire attaches to the same bolt that the safety chains are atttached to. Clean the area up and it should be fine.

First of all, congratulations! Your trailer lights work. I've seen so many that don't. I thought for a long time that trailer lights were just reflectors. I agree with the consensus here -- replace your ground. Sounds like you don't have a good connection or it has deteriorated.

My left light doesn't like to come on until the lights have been turned on for 10 minutes or so. I'll test them out before I leave, and curse the blazes out of the light for never working, but then I'll look back in my rear view, and it'll be shining like a star. Boy I can't wait to ditch this trailer

mine are the other way around...they work perfectly in the driveway but about 10 minutes down the road, my brake lights start illuminating the running lights as well. Left turn signal ... yep all the running lights flash. There's a short somewhere and I'm so fed up with it I think I am going to replace everything.

Jake,

I was working on my power boat trailer lights 2 weeks ago, they were doing exactly the same thing (except in the driveway). The ground wire broke off at the tounge, and I did not have the hitch on the ball so it was not grounding through the chassis. It seemed that the brake current went to the lights, throught the common side of the brake / running light bulb, throught the running lights to a lesser potentioal or ground in the vehicle. Re-attatching the ground fixed it. Sounds like yours is a ground problem as well.

Thanks for the tip! - if it is, it's probably a ground problem with the isolator I installed in my RV recently. I installed a new wiring connector on my trailer because the ground wire broke off a couple of weeks ago . I also installed a fresh ground screw into the trailer toungue to be sure when I redid everything.

I installed the isolator in my RV so the trailer lights will have their own fuse. While coming back from Tradewinds this January, I had one of my trailer side marker lights short out and it took out ALL my running lights on my RV as well as my antilock brake unit. I imagine the lighting system was pretty overloaded with all the marker lights on the RV before I put the trailer wiring in (there was no hitch on it when I bought it). I suspect that it was related but I also began to have an intermitant Engine Management Computer problem that kept getting worse and worse on the next trip and almost kept us from getting home (turned a 5 hour trip into 13 hours). After four days of diagnosing because the computer wouldn't give any fault codes, several engine sensors were needlessly replaced and I ended up finally replacing both the ECM and the Anti-Lock Brake Computer on an RV with 30k miles on it (CHA-CHING).

Four hours to install a $35 trailer lighting isolator unit? Priceless.

Thanks to all of you for your advise. I will use your guidance to fix this problem.