Trailer Wiring Problem

[rjbarry]

I have a trailer wiring problem that has me puzzled. Trailer tail lights, brake lights, left and right signal lights, and emergency flashers all work correctly by themselves. When the car lights are on or brakes are on, the left signal works well, but the right signal also flashes dimly. Likewise, when the car lights are on or brakes are on, the right signal works well, but the left signal flashes dimly. I suspect a ground problem, but don't have a tester. The trailer has a 4 pin connecter. I cleaned up the ground at the trailer side of the plug and at both tail lights on the trailer, but that didn't fix the problem. I sure would appreciate any suggestions for correcting this problem.

[morpho]

i swear to god trailer lights are the most frustrating thing god has ever made if its working one day tomarrow its broken man good luck i wish i could help the one bit i can add is a tester is only 4 bucks at checker ect and will server a lifetime

mopho

[cheesehead]

Do you have the same problem with a different trailer? I suspect your problem may be with the wiring on the tow vehicle.

[rjbarry]

mopho,
Thanks. I actually have a VOM somewhere, but can't find the darn thing now that I need it. I guess I'll be getting a replacement sooner than later.

[rjbarry]

cheesehead,
Thanks. Good suggestion. Unfortunately my friends with trailers have bigger vehicles with different types of wiring connectors. I'll look for someone with a similar trailer and see if the problem is in the vehicle wiring.

[Valv]

I would suggest a tester, $ 10 at Walmart gives you an electrician multipurpouse type.
I am sure it's ground, but it's impossible to fix by posting here, you'll have to test each light.
Chech the 2 bolts that hold each light on trailer (if it has any) thay are the ground contact.

------------------
Val Vignati

www.kvesurplus.com
[email protected]

[minnesota mac]

It's the ground. Some were you have a loose ground. Almost all trailer wiring is caused by a faulty ground. And rule #1 the hitch is not the ground. If you do not want any problems make sure the ground wire is run through the plug. Check for a broken or lose connection. Good luck

[Mike89]

Here's a new one I found, at least for me.I bought an older 14 foot lund and the lights on the trailer were no good. So after replacing them they didn't work properly. So after a couple hours thinking of all the different problems and trying to correct the situation I discovered the trailer it self was the culprit!! It's a tilt bed trailer and the ground between the sections just was not good. Made a jumper to go between them and all is well!! Just some info that might or might not help you. Good luck and good fishing!! Mike89

[MuleSkinner]

I made some simple alligator clip jumper cables just for testing my trailer lights. Then I just used the trolling battery for 12 volt power to test lights. Then you might be able to figure out if the trailer wiring is the culprit (probably is).

I have an old trailer. No end to light problems, until I mounted the lights up on PVC trailer guide ons. Now, they never touch water. Also, had the problem of the wrong bulb dimly lighting. It was frayed wiring. I simply put in new wire set, including wire grounds. As many others have said, using a wire ground eliminates many problems. Using the frame as a ground just seemed to be a continual headache.

[FishinLogician]

I agree on the ground as suspect as well. Whenever I've tried to upgrade lights or I simply disconnected the wires for something simple, the lights were screwed up. I got so upset I cursed a blue streak. Hope the neighbors didn't hear it. Both times it was ground related.

[McGurk]

not an answer, but a hint to stop new problems. just unplug the trailer wiring when unloading and loading you boat. no current means no problems. while rigging your boat to drive away with a meal of fish be sure to reconnect your trailer wiring before you leave!!!

[hydro]

Here is your solution.

1. Make sure that the white wire in the harness is securely grounded to your vehicle in an area that will not get wet and corrode. Interior is best and use star washers when you screw it the the vehicle frame.

2. Run a white wire directly from the trailer pigtail to each rear light assembly, and ground it to the fixture's brass and the frame of the trailer. Use "star" washers everywhere.

This will eliminate the trailer frame functioning as a ground path and your problem will go away! The clue here is in your description of the problem where both turn lights flash, indicating a series parallel circuit resulting from a poor ground in the trailer frame.

[Uncle Grump]

When working on trailer wiring - espec. if you think its a ground problem, never over look the ground wire in the tow vehicle. I had a ground problem a could years ago I just couldn't find/fix. Finally tore open the vehicle wiring in desperation, the ground wire was bad. Fixed it and the problem.

UG

[rjbarry]

Hydro,
Thanks a million! You nailed the solution. Previously I had grounded to the trailer frame at the pigtail and also ran grounds from each rear light to the frame.
On your advice, I ran an additional ground from the pigtail to each of the rear lights. It worked like a charm. Thanks again.

I'd also like to thank all of the others who took the time and trouble to offer their suggestions for resolving this problem.