problem with my trailer lights

[ngt]

Having an issue with my trailer lights. When my headlights on my car are on, the trailer lights don't work. When the headlights on my car are off, the trailer lights work perfectly. Any ideas? is it something with my car? The tail lights on my car and back blinkers work with the headlights on. There is a slight issue. When I turn my headlights on, the blinker goes faster than when the headlights are off. Could there be some type of short or something in my car? Or do you think it could be a wiring issue with the harness the guy installed in my car that plugs into the trailer. My car has the blinker issue even when the trailer is not hooked up. (blinker going faster when headlights are on)

any help would be appreciated. I don't want to get stuck out somewhere because the sun went down.

thanks!

 

[tashasdaddy]

Re: problem with my trailer lights

wiring issue with trailer, probably ground. or crossed wire, wrong bulbs, or a blub in backwards. http://www.accessconnect.com/trailer_wiring_diagram.htm

 

[Silvertip]

Re: problem with my trailer lights

There is also something wrong with the vehicle wiring because with the headlights off the trailer running lights should not be on. Rapid flashing of turn signals indicates you do not have a heavy duty flasher installed in the fuse panel. You need to start with the tow vehicle and verify that the wiring to the plug is correct. Just because everything on the car works does not mean the correspondiing function on the plug is correct. When you have that correct then move to the trailer. The trailer is easy to check if you have a battery charger. Connect the ground lead of the charger to the white wire in the plug. Put a nail in the positive clip and touch each of the other three terminals. The corresponding functions should work. The signals won't flash but that's of no consequence as all you are concerned about is that they light.

 

[Bondo]

Re: problem with my trailer lights

Ayuh,... Check the Grounds,... Sounds like you're missing some or 1...

 

[ngt]

Re: problem with my trailer lights

wiring issue with trailer, probably ground. or crossed wire, wrong bulbs, or a blub in backwards. http://www.accessconnect.com/trailer_wiring_diagram.htm

I checked the ground wire going to the trailer and it was broken off. I can't get the screw out because it's rusted/stuck in there so I'll have to drill it out and rewire it up. Hopefully that will fix the problem.

wondering though...

Why would the lights work without it when my car's headlights are off, but then when they are on, the ground on the trailer is needed??

Also, what bulb? bulb in my car put in backwards? I have had the fast blinker thing going on since I got the car. Again, that issue is only present when the car's headlights are on. The trailer lights are brand new from the store and wired by color.

thanks for the help!!! I hope it clears up the issue. I would drill it out now and test it but it's 6:30am here and I don't want to **** off the neighbors.

 

[ngt]

Re: problem with my trailer lights

There is also something wrong with the vehicle wiring because with the headlights off the trailer running lights should not be on. Rapid flashing of turn signals indicates you do not have a heavy duty flasher installed in the fuse panel. You need to start with the tow vehicle and verify that the wiring to the plug is correct. Just because everything on the car works does not mean the correspondiing function on the plug is correct. When you have that correct then move to the trailer. The trailer is easy to check if you have a battery charger. Connect the ground lead of the charger to the white wire in the plug. Put a nail in the positive clip and touch each of the other three terminals. The corresponding functions should work. The signals won't flash but that's of no consequence as all you are concerned about is that they light.

I was thinking that there was something wrong with the car wiring. But, the trailer's lights aren't just on when the headlights are off. They only go on when I hit the brakes or turn the blinker on. As I believe they should. That part all works fine when they headlights are off. As soon as I turn the headlights on, I get nothing from the trailer tail lights at all when I hit the breaks or anything. Hope that made sense...and sorry if I'm missing something. I'm new to this and am trying my best to understand.

 

[Jersey John]

Re: problem with my trailer lights

If your vehicle has the converter box for the trailer wiring ( seperate turn and stop light's on tow vehicle) I would check that. I had a ford escort with seperate turn stop light's and the converter shorted out and caused all sort of neat problem's through out the car. Just something to look at.

 

[David Greer]

Re: problem with my trailer lights

I just paid a lot of "tuition" to learn about this problem. See if this helps.
Vehicle= 1997 Tahoe; trailer lights added by dealer in 2001; recently discovered issues. The lights went squirrelly as you described only when the trailer was hooked up, lights on. B/c the trailer provides a whole 'nuther grounding route, a tester might not tell the whole story.

The problem we found was that in the vehilce's harness there was a white wire, undedicated, that one would assume was a ground wire, and therefore the previous guy grounded it. Turns out it is some mystery brake wire, perhaps for an auxilary high brake light you sometimes see. When it was ungrounded, the primary problem was solved. i hope that is your problem and this saves you 7 hours of mechanic time.

We also found that on one of my trailer lights, wiring was switched causing a back-feed. So what makes this process hard is the fact that the trailer may appear to work right but is causing problems elsewhere. If you are able to do this, try a couple of different trailers and same-model tow vehicles (my mechanic poked around under another Tahoe to help fix mine.

The rapid flashing is a built-in warning of a short on GM vehicles and perhaps others.

Some GM's have a seperate module (circuit) for the trailer light harness but my guess is yours, like mine, doesn't.

A difficult issue is the possibility that your properly wired harness has a slight cut somewhere along the line causing a ground/short.

Also: brand new lights can be defective. That will cost a lot of hours b/c you assume they work right at least once!

In my high-slat environment I am always surprised if everything works. Good luck.

 

[ngt]

Re: problem with my trailer lights

thanks guys,

I drilled out the screw and set the ground back up. Now here is what happens...better than before, but still with issues.

When the headlights are off, everything works perfectly.

When the headlights are on, the orange lights on both sides of the bottom of the trailer are on and the driver side tail light is on, w/ working blinker. (wasn't happening before) But, the passenger side is super super dimm...like you have to squint to see it on.

When the headlights are on and I hit the brakes, all of the lights on the trailer go out as the brake lights get brighter on the car (like normal brake lights do).

does that narrow it down at all?

 

[Jersey John]

Re: problem with my trailer lights

What kind of car or truck?

 

[ngt]

Re: problem with my trailer lights

What kind of car or truck?

1999 infiniti g20

 

[Jeep Man]

Re: problem with my trailer lights

Do a simply test. Unplug the trailer and test the plug on the car with a meter or small 12 volt test light. Connect one side to the white ground lead and then test the other three by connecting the other side of the light/ meter to the other leads one at a time. Test the left and right signal then the running lights. If all works well, THEN move back to the trailer.

 

[David Greer]

Re: problem with my trailer lights

try running a dedicated ground wire instead of grounding to the trailer. The trailer ground will corrode out rather quickly anyway. But I still say the problem is at the vehicle, or a combo of vehicle and reverse feed at a trailer light. Even an factory or dealer installed light kit inthe car can be wrong, as I learned.

 

[relstabw]

Re: problem with my trailer lights

Check the bulbs in the tow vehicle and in the trailer lights. The two filaments in the bulbs can fuse together causing all kinds of crazy problems. I would also check the trailer lights especially on the side you said was dim. It is possible on the type of trailer lights with two bands as opposed to an actual socket to install them backwards.

 

[FishnMike]

Re: problem with my trailer lights

You're getting feedback through the tail light circuit that's why the problem occurs when your headlights are on. You either have some wires crossed, particulary on one side of the trailer you have the taillights hooked to the tail lights on the car and the turn signal on the trailer to the turn signal on the car but on the other side you have the tail lights on the trailer hooked to the turn signal on the car. Or you have some bad insluation between the wires. One more possibility is any places the wires have been spliced, if not taped properly the turn and tail light wires are touch.

I went through this a few weeks back when my dog bit the wires on my trailer.

FishnMike

 

[beezee28]

Re: problem with my trailer lights

Just curious, what do you tow with your Infiniti G20? Nothing big and heavy I hope.

 

[David Greer]

Re: problem with my trailer lights

on the car's harness, someone wired a white wire to ground but it is really an extra brake light.

 

[kamby]

Re: problem with my trailer lights

on the car's harness, someone wired a white wire to ground but it is really an extra brake light.

Seen that happen a few times. Sometimes they still work and your relying on the hitch and receiver to ground the lighting out. Does provide some ground but not enough specially at full load...

 

[David Greer]

Re: problem with my trailer lights

no, the problem is that what anyone would assume is a ground wire isn't a ground wire but is a hot wire. Nothing bad happens until it' shooked to a trailer and the backfeed occurs. 10 mechanics will see the grounded white wire and reasonably, but incorrectly, assume it's grounded as it should be.

At least that's what we found on day 3, and it fixed everything.

 

[ngt]

Re: problem with my trailer lights

Just curious, what do you tow with your Infiniti G20? Nothing big and heavy I hope.

still trying to figure this one out. The problem ended up being with the car wiring and not the trailer. It's somewhere in the brake light setup in the car. Nothing weird happends to the lights until I put my foot on the brake while the blinker and headlights are on. I just need to get in there and troubleshoot.

as far as what I am pulling....ended up with a 12 foot aluminum. I've pulled it on the freeway and in and out of the water with the boat with absolutely no problem at all.