Newb Problem Trailer lights..

[Jims5543]

I am having a problem with my trailer lights and not sure where to look.

I do not have any driving lights when the truck lights are on. Brake lights work perfectly, directional too. Just no running / driving lights for nighttime.

I am going to recheck my grounds and make sure everything is right.

I just installed 2 new rear lights, taking off the old school bulb lights and putting in LED lights and they function as told above fine.

I am running a 4 wire setup on a 1999 Challenger 1800 trailer behind a 2007 FJ Cruiser with factory tow kit.


One thing I am going to try, I have a utility trailer, I am going to hook that up and see if it lights up just to take the FJ Cruiser out of the question.

Anything I should be looking for?

Thanks in advance.

 

[Seadoobuddy]

Once you hook up the other trailer you will get more info on whether it's the boat trailer or the truck that is the problem.

That is a good diagnosed idea ....get one thing out of the way first then dive into the problem with the other.

 

[LouDoo]

I've found through the years that trailer light problems are almost always with the ground. Try grounding the white wire to the trailer frame, grind or scrape off the paint to a small area of the trailer frame drill a small hole and ground the white wire.

Lou

 

[Coastiejoe]

The brake lights and directional lights are the same lights. So it makes sense they are all working. Testing via the other trailer is smart as it will help you, or us, figure things out. As Lou mentioned, the ground is almost always the issue. But,,, since your other lights are working and working correctlyu, as in not dimmed or flickering, I'm betting it is the feed wire for the running lights.

Now, it could be that your vehicle is the issue as many of the new cars use the same bulbs in the rear for markers, brakes and turning lamps. They vary the voltage to accomplish the task. If this is the case with your vehicle, then your feed to the running lights is not getting power.

I would use a meter or a test light to see if the feed wire at the trailer plug is giving 12 volts to the running lights...

 

[Jims5543]

It is the truck. I took a test light and checked each function at the plug point on the back of the truck. The driving lights do not transfer to the plug. The brakes and directionals do, just like on the trailer.



Heading to the FJ Cruiser Forum to see if this is a common problem with the tow kit.