Rear Light Problem

[wingbone]

When hooking up lights, how do you keep the L and R lights separate from both activating. This is actually on my dump truck but they have the same exact lights on both. It says to hook up the turn signals and brake light to the same wire (red on the lights), but how do you keep it from activating the other side if both turn signal wires are also inline with the brake wire? I know I'm overlooking something obvious.

 

[George2615]

I don't know what dump truck you have so can't comment on your wire color but for basic trailer (lighting only) wiring you need to hook up 4 wires. left turn, right turn, parking lights, and ground. Trailers with brakes require more wiring and a brake controller in your truck.

You'll need to install a trailer plug on your truck. Then you'll need to connect the plug wiring to each of the above. If your not electrically inclined most any garage mechanic can hook it up for you in less than an hour. I've attached a file showing the standard 4, 6, and 7 pin color coded plugs. Brake light signals are sent through your turn signal wiring.

 

[Skyco]

That doc shows black for tailights on the 4 pin, it should be brown.

 

[wvpolekat]

The brake lights should not be tied to each other. They are 2 separate circuits. At least at the trailer. So, when you put your brakes on, both turn signals light up. You don't actually wire "brake" lights to the trailer, just turn signals, the vehicle takes care of which one is doing what.

 

[wingbone]

I haven't even gotten to the trailer plug yet. I need to isolate my L/R tail lights on the truck and I guess subsequently this will allow me to hook up my plug. The lights on my truck are just like regular, round lights that slip into a cutout circle with rubber ring. They have a white, red, and black wire. The white is the ground, red is brake/turn, and the black is tail or running lights. The problem is, I'm supposed to hook up the brake wire from the truck to the red wire on the lights. This powers the brake lights fine. However, the red wire on the light is also for turn signals. When I hook up those, this is now sending flasher/turn signal power to both lights since they are also hooked to the brake light wire. How do I isolate the turn signal from powering both sides. Do I need to use diodes in some form or fashion?

 

[wingbone]

The brake lights should not be tied to each other. They are 2 separate circuits. At least at the trailer. So, when you put your brakes on, both turn signals light up. You don't actually wire "brake" lights to the trailer, just turn signals, the vehicle takes care of which one is doing what.

Yeah, this is really the problem I'm having and I was explaining further in my post while you were posting this. The truck at one time probably handled this upfront but I'll probably catch the devil trying to figure out where.

 

[Diamondpilot]

You will need a tail light converter. Takes 5 wires in and converts them to 4 wires out. They run $15 or so and will take care of you.
The 5 in are R Turn-L Turn-Brake-Ground-Running


The 4 out are Right-Left-Running-Ground


Chris

 

[wingbone]

Thanks, Chris.
I might actually be lucky and you might be able to give me a little more help. I had bought a used trailer hitch for my Chevy Uplander which came off of a Chevy Venture. This also came with a Curt wiring Harnes from the Venture. Well the hitch was the same but the wiring harness did not match. I believe I might be able to use this as the converter. It has 5 wires going in: White/Brown/Yellow/Red/Green. Coming out to the trailer side is White/Brown/Yellow/Green. I'd bet a million dollars this is doing the same thing. Would you suspect brown to be running lights and red to be brakes? Yellow and Green turn signals?

 

[wingbone]

Well, that thing I had didn't work. I really don't see why it wouldn't. It would allow the tail light(brown wire) to power the light both ways which makes sense. It seems like the other would have worked too and I tried it from both ends with a battery.

 

[Diamondpilot]

You need a converter. Get one at WalMart or any Uhaul. Simple hook up. It has a box with electrical components that are like magic to me but its what you need if I am understanding you correctly. Many newer vehicles need them so you are not in new territory.

Chris