Trouble shooting trailer wiring

[Andy in NY]

Okay, its not my boat trailer but I firgured you guys could help me.

My wood trailer is a 4x6 trailer bought from one of the big box stores and is about 1 1/2 years old. I bought it over the summer and one of the tail lights never worked. I replaced the bulb, but still nothing. Then the other side tail light stopped working. Everything else works except for the tail/running lights.

Where should I start the troubleshooting?

 

[tashasdaddy]

Re: Trouble shooting trailer wiring

every trailer owner should have one of these.. http://www.iboats.com/Boat_Trailer_...z.54343--**********.430681326--view_id.217589

ground is usually the #1 problem.

 

[Silvertip]

Re: Trouble shooting trailer wiring

The circuit that is not working is on the BROWN wire in the harness. follow that wire from the connector all the way back to each light. Sometimes the wires at the light simply push into a hole in the light and a very poor connection is made inside the light. Remove the lens and look at those connections.

 

[Mark_VTfisherman]

Re: Trouble shooting trailer wiring

First you need a something to check for power- a little thing with an alligator clip on one end and an ice-pick on the other that has a light in it. Check for power at the wires in the back of the light housings. Often these are merely metal "pinch" connectors that cut into the wire and they corrode there.

Second, the contacts for the bulbs in those cheap lights can oxidize and not work well. Happened all the time on my boat trailer, but one day I cleaned them all up and coated everything with dielectric grease (Napa) and they have been 100% for two seasons now. Amazing.

I think that should make it work for you.

If you don't have any power at the wire to the light, keep working upstream until you find power and then you know about where the fault starts.

 

[Wee Hooker]

Re: Trouble shooting trailer wiring

You can get a voltage/resistance meter from Harborfreight for $3. Good investment to quantify what's going on. You might also check your output from your vehicle. Wouldn't be the first time somebody chased a "trailer " problem that wasn't in the trailer