Trailer Running Lights Issue

[big guy]

Just changed tow vehicles on the weekend, retiring our '96 Buick Regal (4 sale by the way) in favour of a 2000 Nissan Xterra. The trailer lights always worked amazing with the Buick, but when I hooked the Xterra up to the trailer on the weekend to test them, everything works except the running lights for the main bulbs. The little side lights at the back of the trailer light up, but not the main lights. Signals work, brakes work, but no running lights.

 

Now, I have heard that vehicles with orange turn signals can be a problem when it comes to 4-pole trailer light assemblies, does anyone know if that could be the issue, or failing that, have any other suggestions as to why I am experiencing this problem?

 

Thanks in advance

Edited June 14, 2011 by big guy

[Terry]

they have to light bulbs

you need the trailer adapter

 

http://www.jcwhitney...d1705j1s21.jcwx

 

maybe it's just a guess

Edited June 14, 2011 by Terry

[Bernie]

Try the running lights, signals and the brake lights at the same time.

If it works OK then it's wired proper.

If the side marker lights are working this indicates that the running light circuit is working and the problem is with the trailer.

It's also possible the ground circuit is bad. Grounds not working will cause the lighting to find a ground through the bulbs that have the least resistance and light up others.

[Kerry]

Try the running lights, signals and the brake lights at the same time.

If it works OK then it's wired proper.

If the side marker lights are working this indicates that the running light circuit is working and the problem is with the trailer.

It's also possible the ground circuit is bad. Grounds not working will cause the lighting to find a ground through the bulbs that have the least resistance and light up others.

 

you should just run a new ground somewhere to the body of your vehicle where the wiring harness is coming out rather than relying on a factory ground wire.Keeping it closer to the trailer should help with ground issues.

Kerry

[HTHM]

On my Nissan Quest, I needed a powered harness in order to run the lights. Talk to a hitch place and they should be able to point you in the right direction.

[big guy]

they have to light bulbs

you need the trailer adapter

 

http://www.jcwhitney...d1705j1s21.jcwx

 

maybe it's just a guess

 

 

Ya, that was what I eluding to, some kind of adapter, but the guy we bought it off of had no troubles with his trailer lights, so it seems strange. I can get a similar adapter at TFC, but I will use it as a last resort.

 

Thanks

[Terry]

On my Nissan Quest, I needed a powered harness in order to run the lights. Talk to a hitch place and they should be able to point you in the right direction.

 

yeah that's what I meant by " trailer adapter"

 

lots of vehicles that have separate light bulbs for brake and tail lights need that powered harness to work right

[big guy]

To everyone that replied, I have checked the lights with a tester at the vehicle and all female ends light the tester in the appropriate way, so I know everything is right to that point. The hitch and wire harness on the truck is after factory and appear to be properly installed. It's impossible for me to see where the vehicle ground is grounded to, but I will check the trailer ground, which is on the tongue.

 

Thanks to all

[Bernie]

SOme newer vehicles that use a controlled module at the back to operate the lighting need a powered adapter.

But others that have separate signals and brakes need an adaptor with diodes to block brake lamp operation from crossing over to the signal side.

If this has been done by the previous owner it is possible there may be a defect in the adaptor.

But when you said the side markers were working this is not likely your issue.

Did you try all lights at the same time?

[Rich Clemens]

wouldn't be a fuse would it ? I recall coming up the QEW a fews years back. No running lights, but the signals worked. Ended up being a blown fuse. Replaced the fuse and all was well.

[big guy]

I just checked all the lights at the same time, brakes worked, signals worked, but no running lights.

 

Now, another strange thing about all this is when I wiggle the trailer lights a little, the side markers turn off and on, still no main lights however. Is this an indication that, as Bernie mentioned, that the lights are grounding out through the main bulbs?

[big guy]

wouldn't be a fuse would it ? I recall coming up the QEW a fews years back. No running lights, but the signals worked. Ended up being a blown fuse. Replaced the fuse and all was well.

 

Everything works on the truck end, it's the running lights on the trailer only that are not functioning.

[Bernie]

I just checked all the lights at the same time, brakes worked, signals worked, but no running lights.

 

Now, another strange thing about all this is when I wiggle the trailer lights a little, the side markers turn off and on, still no main lights however. Is this an indication that, as Bernie mentioned, that the lights are grounding out through the main bulbs?

 

What/where are you wiggling?

At the trailer lamps at the back or at the front plug in?

[big guy]

What/where are you wiggling?

At the trailer lamps at the back or at the front plug in?

 

At the rear of the trailer, wiggling the lights that are attached the trailer.

[Bernie]

OK, check the lights where they are fastened to the trailer. Depending on the style, most will get their ground at the point where they are attached to the metal frame of the trailer. Rust can develop in between and create an open ground circuit.

Also check inside each lamp housing and look for green corrosion where the wires come in and around the base of the bulbs.

[big guy]

OK, check the lights where they are fastened to the trailer. Depending on the style, most will get their ground at the point where they are attached to the metal frame of the trailer. Rust can develop in between and create an open ground circuit.

Also check inside each lamp housing and look for green corrosion where the wires come in and around the base of the bulbs.

 

The lights are the sealed kind, so I can't check inside. I thought about last night, but alas, can not do it. I will check the grounds right behind the lights on the bracket.

 

It just seems funny to me though that, all of a sudden, I started having this issue. I know trailer lighting is notorious for "issues", but it seems odd that getting a new tow vehicle started all this. Oh well.

 

Thanks for your help

[Rich Clemens]

Everything works on the truck end, it's the running lights on the trailer only that are not functioning.

 

 

Same as ours - all the truck lights worked fine. There was a separate fuse box in our Dakota under the hood that had separate fuses for the trailer lights. May not be the same scenario for you. Hope you can get it tracked down.

[HTHM]

Same as ours - all the truck lights worked fine. There was a separate fuse box in our Dakota under the hood that had separate fuses for the trailer lights. May not be the same scenario for you. Hope you can get it tracked down.

Good call Rich!, I had the same with my Nissian, check your fuse box for a fuse called trailer, mine was not seated properly and as a result I had no lights at all