Simple Wiring Question...

spalind

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I am attempting to wire in some new turning signals that are being mounted in my bumper. They are LED lights and have a red, white, and black wire. The White is the obvious ground. In connecting them to the regular turn signal lights however, the stock wires are green, black, and blue...How should this be wired up to work correctly?
 

spalind

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I believe LEDs need a different flasher.
I believe you are right...hooked them up correctly...BUT...with the truck lights on the turn signal works just fine. Without the truck lights on the turn signal only flashes VERY, VERY faintly...I assume it needs some sort of relay, resistor or the like. Any ideas?
 

_

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Dan, this is probably because there is a back feed due to the flasher relay not seeing enough current draw. On almost all vehicles, if you install LED lamps you will need to swap out the factory turn flasher for an aftermarket unit designed for LED. Most of the LED flashers will have an additional GND wire extending from it that will need to be properly grounded to the chassis.

I do not recommend installing resistors to emulate the load of an incandescent bulb. To do so, you will need to install a 12 ohm, 20watt resistor in each lamp circuit and this may prove to be a liability down the road. In addition to a liability, you will need to mount/protect the resistors from damage and mount them in a manner they may safely dissipate heat. (The heat will be that of a 1-watt brake lamp)

Also, be sure you have the vehicle's correct run lamp and turn lamp circuit going to the correct color wire on the LED lamps.


I believe you are right...hooked them up correctly...BUT...with the truck lights on the turn signal works just fine. Without the truck lights on the turn signal only flashes VERY, VERY faintly...I assume it needs some sort of relay, resistor or the like. Any ideas?
 

loufish

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Some newer vehicles have the BCM (Body Control Module) do the turn signals, there is no flasher...I thought I've read somwhere that the LED manufactures were going to have a built in resistor board of some sort to emulate the original bulbs to keep the BCM happy...
 

spalind

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Dan, this is probably because there is a back feed due to the flasher relay not seeing enough current draw. On almost all vehicles, if you install LED lamps you will need to swap out the factory turn flasher for an aftermarket unit designed for LED. Most of the LED flashers will have an additional GND wire extending from it that will need to be properly grounded to the chassis.

I do not recommend installing resistors to emulate the load of an incandescent bulb. To do so, you will need to install a 12 ohm, 20watt resistor in each lamp circuit and this may prove to be a liability down the road. In addition to a liability, you will need to mount/protect the resistors from damage and mount them in a manner they may safely dissipate heat. (The heat will be that of a 1-watt brake lamp)

Also, be sure you have the vehicle's correct run lamp and turn lamp circuit going to the correct color wire on the LED lamps.
So an LED compatible flasher should do the trick as long as I ground it properly? Why the difference between working and not working when I have the headlights on vs. off?
 

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Dan,

Great question and hard to answer without diving into a proper wire schematic. This may be the result of ground loops and/or the method the factory activates the run lamps, or the method the factory grounds the run lamps.

If your OEM lights used a separate bulb for Run and Brake, insure the run lamps have a constant BATT GND and the activation for the run lamps is via the +12V. If the run lamps receive a constant +12V and are activated via Batt GND (which some foreign car MFG practice) this will pose a problem.

Also, if you have what is commonly referred to as a 5-wire tail light system (having independent brake lamp from turn lamp,) and are now trying to alter this to a 4-wire system (sharing the brake lamp and turn lamp function through the same filament,) you will need an adapter to accomplish this.
 

Co-Dog

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Sounds to me like you have them wired incorrectly. White is not usually a ground.

My money is on the Black being ground.......Red - Brakes........White - flashers.

If you have them wired backwards, you will get the problems that you described. Chromoly Kid just went through the same thing because he had an LED running light in the socket backwards.
 

spalind

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Sounds to me like you have them wired incorrectly. White is not usually a ground.

My money is on the Black being ground.......Red - Brakes........White - flashers.

If you have them wired backwards, you will get the problems that you described. Chromoly Kid just went through the same thing because he had an LED running light in the socket backwards.
The white wire from the light has the little "0" shaped end connector on it. Am I incorrect in stating that kind of end connector is for the ground?
 

_

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It is real simple to identify the proper wire colors. Remove the lamp and light it up with your vehicle's battery. The wire you discover that must be attached to properly illuminate both run and stop/turn is your common wire (GND). Assuming a wire is GND because it has a "0" on it is just that, "An Assumption". Before you go any farther, test it on a battery outside the vehicle and properly identify the true wire color functions. You will not damage the lamp if you swap GND for +12V during your evaluation process. Try all combinations until you have reached an accurate conclusion. Then, reinstall the lamps in your vehicle per your results and see if it all works properly. You may still need a LED flasher, but at least you will now be confident the lamps are properly wired.
 

ChromolyKid

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Sounds to me like you have them wired incorrectly. White is not usually a ground.

My money is on the Black being ground.......Red - Brakes........White - flashers.

If you have them wired backwards, you will get the problems that you described. Chromoly Kid just went through the same thing because he had an LED running light in the socket backwards.
Yes I did! I concur with Co-Dog's thought on black being ground, and red brakes. My wires are purple, blue, and brown... but I'm not about to try to explain that mess. Isn't black generally ALWAYS ground, red power, and white signal (or switch)?

Going back to my problem though, be sure to check all the little seemingly insignificant things. ALL of them. LED's and running lights do funny things when something simple isn't right and will send you on a wild goose chase. That's just my two cents. Good luck!
 

Motelcambodia

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The white wire from the light has the little "0" shaped end connector on it. Am I incorrect in stating that kind of end connector is for the ground?
Make sure your wiring it to the wires that go to the bulb that faces forward not the side marker , The side marker will blink differently when the lights are on and will mess up your LEDs. Its not wired the same and has no real ground.
 

philofab

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White is ground.
Black is (dim) running lights +12v.
Red is Brake (bright) lights +12v.

Old trailer stuff (Lights & Brake controllers) are UL color coded. Remember that LEDs are diodes and require the current to work in the correct direction, regular light bulbs do not care.

On a Nissan the ground is black, and most likely the green is turn signal, and the blue will be running lights. I need to know year, make, model, and front or rear to know for sure.
 
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