Problem with trailer light

[jmhusby]

We have a 12' aluminum trailer that we use to haul our mower around to cut several lots that my son owns. The last time we used it the right turn signal won't work. If you unplug the light and use a test light it will blink but won't work if you plug it in. Tail light works on it. Does it on two different trucks. Very puzzled.?

[damon91]

Make sure all of your grounds are good. The light to the trailer, and the wiring harness ground to the trailer. if its an aluminum trailer its possible the the connection points have oxidized. I like to use electrical grease on connections and plugs, it helps keep goofy problems away due to corosion.

[rokon2813]

Try a new bulb too. Sometimes the bulb can be bad and not look bad.

I've even seen where the little "bump" on the base of the bulb was dented from time and didn't make a connection.

Also, if it the style light where the wire is just pushed in behind a tab of metal, they lose connection there too.

[HubbardRA]

First thing that I do is hold the bulb up to the light and look to see if both the internal filaments are still intact. If they are, then, like Dan said, I have had several bulbs get the dent in the solder on the end of the bulb and not make connection. Usually when this happens you will either have a tail light that burns or a turn signal that flashes, but not both. I have taken a soldering iron and built the contact back up to where it should be and had the bulb work again when I put it into the socket.

Bulbs are cheap enough that I just replace them nowadays. I only use the soldering iron if it happens at a time that I cannot easily get another bulb. Most of the time I keep a couple hanging on the wall in my garage now.

[jmhusby]

We tried a new light. This is one of those where the light sits in a rubber seal all the way around it. You just plug into the light and push it into the rubber seal. No bulbs to change. Works the same with a new one or the old one and two different trucks.

[timflury]

Troubleshoot by switching the wire for the right turn signal with the wire for left turn signal.

Post your results.

[HubbardRA]

I test the wiring by sticking a straight pin through the insulation till it touches the wire, then connect a jumper from the hot terminal.

You can do this along the wire from the light backward toward the connector till you find the location of the break in the wire. This is assuming the light will burn when a jumper is attached to the power wire at the connector, then connected to the light wire at the unit.

Good luck with finding the problem.

[jmhusby]

Thanks for all the hints. Found the problem. Talked to the mechanic that takes care of my older truck and said as long as the tail lights work the ground is okay and I should change the plug to the light. bought a new plug and went through the effort of putting it on and making sure all the connections were good and plugged it in and the same thing. Got the tester out and unwrapped the plug to the truck and checked the wire coming back and nothing. Moved it around and it started working. Wrapped it back up and it still works fine. bought a new end to plug into the truck and will change it if it quits working again. Kind of a screwy plug as it has two ground wires and two tail light wires going into the plug. Thanks again for all the suggestions.

[Mike]

I can't understand why somebody doesn't come up with a new system for trailer plugs, they just don't last