Trailer wiring question

[aczlan]

If you connect the green and yellow to the red, your turn signals will operate like hazards when you signal left or right. You need to isolate them with diodes as others have mentioned.
The problem with using the blue brake wire is that it is not a full 12v until the brakes are applied firmly, it varies from about 2v to 12v depending on how hard you stop.

Good point. Diodes on the green/yellow wires are your best bet if you want to use this in the center.

Aaron Z

 

[Smallplot]

Here is a thought. Before attaching the light hook up some wires and check out what they do. Just cut a couple jumper wires and pull directly from your trucks plug. Pay special attention to how it does with right and left turn signal. The outside two lights my flash giving an auxiliary turn signal. In that case you would have to attach the coordinating turn up to the appropriate wire and parking light wire up to the third wire.

There should also be a wiring diagram on or in the package. It may be able to act in several modes depending on how you want it to operate.

 

[MikeA57]

Yeah, I was just going to use it as a rear tail and brake light. It was cheap enough and I knew that 3 quick holes drilled and a simple hookup, I'd have it installed. Then this...

That's a good point about the wire from the brake. I knew that but didn't think about it. Maybe I will just use the diodes. I've got some lying around.

 

[MikeA57]

There is no diagram on the packaging or website. The instructions are printed on the back of the cardboard sleeve. I thought this was supposed to go in the center of a boat trailer and work the way I wanted it to. Just another example of me wanting the world and everything in it to acclimate to my will and not the other way around...

 

[Iplayfarmer]

Even if you hook the center light up with diodes, it's still going to flash when you use either turn signal. The only time it won't is when you brake while you're applying the turn signal.

My suggestion... Connect the black wire to your marker circuit and forget about the red wire. Problem solved. You have a clearance marker light on the back and you don't have to worry about isolating the turn signals from each other.

 

[simoutdoors]

You guys are over thinking this. The ground/neutral is likely provided by the mounting bolts, which is typical in trailer wiring. Now you have one wire for running light and one to connect to each brake light/turn signal.

 

[Iplayfarmer]

You guys are over thinking this. The ground/neutral is likely provided by the mounting bolts, which is typical in trailer wiring. Now you have one wire for running light and one to connect to each brake light/turn signal.

I guess the easy way is to hook up a battery charger and test it. I'd bet that the white is ground, though.

 

[boggen]

someone else said. grab the light, and just hook it up directly to the wiring harness at rear of truck. with some jumper cables or like. and see what happens.

jumper cables being. a couple pieces of wires. ran from wiring harness to cables on light. and piece of tape around each connection.

if need be have a second person help you. as in, applying brakes, left and right turn singles, flashers on/off. turning on / off tail lights.

just a side note, i assume you have ample power for additional lights. but you might have a cheap extra flasher unit. for tail lights. that may not have enough umph to run all the extra lights.

the idea of running lights off the wire to the trailer brakes. has me on edge. just does not sound right. i mean technically it could work. but doing so could cause the brakes not to work correctly on the trailer. or rather make that, the brakes would not apply themselves as good as they did before if you ran light off of the brake wire.

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on another note:

if you are placing this dead center, i would just use it as a marker tail / brake light. and forget idea of turn singles in it. if you had 2 of them and placed each one on left and right side, OK. but dead center. I don't know about the idea of using it as turn singles.

 

[Iplayfarmer]

...if you are placing this dead center, i would just use it as a marker tail / brake light. and forget idea of turn singles in it. if you had 2 of them and placed each one on left and right side, OK. but dead center. I don't know about the idea of using it as turn singles.

The problem here is that trailer wiring doesn't usually have a brake light option. There are marker lights and there are "signal" lights. The same wire runs the turn signal and the brakes. If you apply the brakes, both lights come on. If you apply a turn signal, only that one side comes on (and blinks). The challenge is how to illuminate this center light when the brakes come on, but not blink when a turn signal comes on.

I don't see a good way of doing it. Even a 7-way trailer plug doesn't have a dedicated brake circuit other than the electric brakes. I agree with others that tying into the e-brakes is a bad idea. You could run an extra wire, but I couldn't even tell you where on the truck to pull the power from. Your signal lights on the rear of the truck are likely wired the same as your trialer (i.e. no separate brake circuit)

 

[Iplayfarmer]

New idea...

Is there a way to wire this center light so that it only illumintates when BOTH signal lights are on? This way when both signal lights come on (i.e. when braking) this center light would come on. When only one is on (i.e. when applying the turn signal) the light would not come on. I'm sure there's some kind of relay or something that would require two inputs in order to energize the output.

Oh, Dang! That still gives you a blinking light when you apply the brake while you're turning.

Nevermind. I'm back to just wiring this center light as a marker light and leaving well enough alone.