Trailer Lights

[pointcityfisher]

First off, I feel really stupid but this is annoying the crap out of me.

I wired up a trailer that I have recently rebuilt and am having an issue with the rear lamps. if you are looking at the trailer from the back, this is what happens; both lights are on with the headlights of the truck, however, once I turn on my left blinker, the left light remains lit and doesn't blink. Also, the right light goes out when the brake is engaged. The right blinker works so all is good there.

My initial thought was "okay, I have a bad ground". I immediately took a grinder and went to work. I don't think there is anyway a bad ground could be my problem now.

What say ye? For reference, if it helps, my light kit is the Peterson Light kit with side markers from Lowes

 

[kofkorn]

Check the silly things first.

Remove and re-install the lightbulb in the right hand housing. Sometimes if the bulb is installed backwards or not fully twisted into position, the contacts can make the bulb act funny.

Pay close attention to the two little posts sticking off of the side of the bulb. They are at two different heights on the base of the bulb. They need to go into the proper location on the socket or the contacts don't line up properly. It isn't difficult to insert the bulb in the wrong way and then force it into place, you probably wouldn't even notice it.

as a reference, the wiring should be:

White - Ground
Brown - Tail lights/ marker lights
Green - right (Passenger) stop / turn
Yellow - left (Driver) stop / turn

Good luck!

 

[T Man]

Check the ground on the truck side as well especially if you have a 7 pin connector. I chased a ground problem similar to yours for two days. I rewired the trailer, had good voltage but finally found a corroded ground backside of the 7 pin connector.

 

[pointcityfisher]

I had checked to make sure all wires were hot but have not checked the bulbs themselves as of yet.

Also, my utility trailer lights work perfectly with the same tow vehicle so I had assumed that my truck was okay. However, assuming may be my downfall. I will check that also.

I appreciate it guys

 

[JMichael]

pointcityfisher » Today, 12:52[/url]"]my utility trailer lights work perfectly with the same tow vehicle so I had assumed that my truck was okay.

Are you saying the utility trailer works right because you tried it after you started having problem with the boat trailer or you making the assumption that the util trailer works correctly because it did a week or so ago when you used it last? :mrgreen:
If you did check the util trailer after the boat trailer failed, then I'd say odds are in your favor that the truck is good to go and the fault is something on the trailer.

But it does sound like a bad ground. :twisted: :lol:

 

[huntinfool]

I work on these for a living now. (No more fiberglass)

First, take your test light and check the truck. Hook the ground to the ground of the plug. Turn on your hazards and tail lights. If all are working, you're fine there.

My guess is still a bad ground. If the trailer has any bolted on parts that could be the problem. If it is a tilt trailer, they are notorious for losing ground there. You can do one of a couple things. Run a ground wire to all lights and connect it to the wiring harness up front, or you can make a jumper between all parts. Ie the tilt, the bolt on fender and the fender lights and the bolt on brackets that hold the lights.
I'd also check the mounting surface behind the light, make sure it is clean as the light grounds through the bolts that mount it.

 

[WaterWaif]

Trust no connection till proven clean and tight. As mentioned use known good bulb for what socket is being tested and grounds the same as all connections. Those blue and the white tap splice connectors were a constant problem when I serviced vehicle/trailer wiring and should be eliminated when possible in my opinion.

 

[huntinfool]

. Those blue and the white tap splice connectors were a constant problem when I serviced vehicle/trailer wiring and should be eliminated when possible in my opinion.

Very true, that's one of the first things we do.