Trailer light question

[GreeCguy]

Howdy fellow Bitogers!

The trailer I have been working on is almost done. Wired up the lights today. Good clean ground at all points and mounted them to the rear side of the trailer. Brake lights work well as do the running lights. Problem however is when I turn my turn signal on, both rear lights on the trailer flash like the "flashers" are on. When I turn my left signal on, both trailer lights flash, likewise, when I turn my right signal light on, both trailer lights flash.

Where did I go wrong?

 

[GreeCguy]

BTW, it's a simple five wire set up. Two wires go to left light and two wires go to the right light with one wire to ground.

 

[Sequoiasoon]

Where is ground going? trailer frame or grounded back on vehicle? Maybe check etrailer.com for guides? Is the wiring good at the vehicle? Our scout trailer had a bad adapter plug (7 round to 4 flat pin) and after tracing all trailer wiring through found that adapter had a broken ground tab internally. Somethings worked, some didn't based on ground connection through ball.

My neighbor had one for a boat that needed the reverse lights hooked up as it locked out part of his surge brakes on trailer.

 

[RANDYZ]

Are they blinking at full brightness or dim?
If dim check grounds again. If full I would check the tow vehicle plug is putting out proper signal with a test light.

 

[63Marauder]

you might need a heavy duty flasher

 

[exranger06]

You said it's a five wire setup? You mean the plug that connects to the truck is a five wire plug? Do you have surge brakes or reverse lights? If not, you should be using a four wire plug. One wire is for ground, one is for the running lights, one is for left turn signal and left brake light, and one is right turn signal and brake light. On a five wire plug, you still have those same four wires, plus one extra that's hot only when the truck is in reverse, to disable surge brakes or for reverse lights.

 

[eljefino]

Also check your bulbs and sockets to see if a filament is shorting between parking lights and brake.

Does your tow rig use combined brake/ turn or do you have a "box" to adapt ambers?

 

[Donald]

I assume we are talking about a flat 4 wire connector? If so I would suggest to get it working with a 12V battery and jumper leads. Forget the car. Once that is all set then introduce the car.

I think you need an adapter in the car where it combines the wires to 4. Its got some diodes in it.

Cover the connectors with liquid tape while they are newly crimped. Hope you did not use any of the cheesy blue connectors that allow you to add a wire without a splice?

 

[Donald]

A 5 wire flat plug (on boat trailer) has one wire for reverse (back-up lights) to engage the disc brake back-up solenoid to prevent surge brakes being applied in reverse.

 

[GreeCguy]

Trailer update and more info:

Trailer is a 5 x 10 all metal single axle trailer. No brakes or braking system on trailer.

I hooked my car up to my neighbor's trailer today and all lights worked well. Blinkers blinked at proper times, running lights ran and brake lights glowed. In other words, there's nothing wrong with the car, so it has to be something with the trailer in question.

When I say a five wire hook up, yes, it's a four point connector with two wires running to each light and one white wire that serves as a ground. When I installed the ground, I took my grinder and ground away all the paint, etc. at the grounding point then ran a self tapping screw through this nice, clean, shiny metal, wrapping the ground wire around the screw and then ran it tight into the metal.

When I was "testing" trailer lights, I did not have the trailer hitched to the car, I simply backed up to the trailer, pulled it close and attached the wire hook up without putting the trailer on the ball. Could that be a problem?

Could it be the ground at the lights themselves? It's my understanding that these lights ground to the frame through the bolts and nuts that attach the lights to the trailer frame. The nuts even have an attached washer with "teeth" (for lack of a better word), that "bites" into the metal. Is it possible these "teeth" aren't biting enough? Could I run a wire from one of these nuts/bolts and ground that to the frame? I just painted the trailer so perhaps there is too much paint between light and frame - sound like part of the problem?

When the lights do blink on the trailer, they do seem to blink dimly, (I'm only guessing as this is a new set of lights - but they don't seem as bright as they should be).

Thanks again for the guidance and wisdom

 

[javacontour]

What lights does the tow vehicle have?

I.E. does it have separate Brake and Turn lights?

Is it possible that you have the tail lights and brake lights crossed? I.E. the brake lights are going to the tail light circuit and vice versa?

Yes, it can be the ground on the lights themselves. Current could be trying to find it's way to ground through the other filament of the tail light bulb, cause dim lights on both sides.