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Installing LED Turn Signal Lights Information

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As I am starting to post here, you may notice that I like details and to know why things work the way they work. If anyone finds that I have posted incorrect information, please let me know.


So I just ordered my LED Switchbacks for the front of my Edge. I was reading on the resistors that everyone is installing to prevent the Hyperflash from occurring. The majority of everyone uses the 50 watt 6 ohm resistors. Some older posts showed a person using a 3.8 ohm ceramic resistor so it got me curious. Why is it a 6 ohm resistor is used vs the 3.8 ohm or some other value. First lets take a look at what specs the 3457 bulb has.



category: Miniature
volt: 12.8 / 14
amp: 2.23 / 0.59
watt: 28.5 / 8.26
base: W2.5x16q
glass: S8
filament: C6/C6
fil.res.: 5.74 / 23.7 ohm
m.o.l.: 2.09 inch (53MM)
l.c.l.: 1.1 inch (27.9MM)
i.lumens: 503 / 37.7
cp: 40 / 3
d.hours: 400 / 5000


The car wants to see roughly 28.5 watts at 12.8 volts to think that the bulb is in place and working. So we need the combination of the resistor and the LED bulb to be roughly 28.5 watts. I don't have my LED bulbs yet to measure its amp draw so for now lets just look at the resistor. For reference we will use 12.8 volts. For the resistor, we know it is 6 ohms. First we need to find how much current the 6 ohm resistor will draw at 12.8 volts. To do this we will use Ohm's law which is I(amperage) = V(Voltage)/R(Resistance) So it is I=12.8/6 which is a current of 2.133 amps. Now to find the wattage we use the formula I(Amperage)=P(Power or Wattage)/V(Voltage) So we have 2.133=P/12.8 or 12.8x2.133=P which is a wattage of 27.47 So if we only take into account the resistor, we see that it alone is 27.47 watts which is very close to the desired 28.5 watts. Once I get my bulbs and test them, I will update the post with what the total wattage is that the car will be seeing between the bulb and resistor together.


Now why do we need one resistor per bulb you might ask since the front and back lights are both flashing at the same time? Can't we just use one resistor of the proper size to make up for both bulbs? We that was my thinking until I looked at the wiring diagram. As we know our Edge's don't use a relay for the flasher like other cars. Each light connects to the BCM and its own transistor to control the blinking. This means that we need to treat each bulb individually.


More info to come once I get my bulbs and do some more testing. Hope some of you find this interesting.




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