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hello everyone, I having a problem with my tail lights and I’m hopeful you guys can help. It’s a 06 GT recently one of my tail lights went out so the rapid turn signal started happening so I figured might as well change them all so I changed the main 4/6 lights to LED lights bulbs no wiring just simple plug and play. Here’s the problem, when driving in daylight no problem with turn signals or brake lights. But when I drive at night and use the headlights then my turn signals don’t work, the lights just stay illuminated and I get the rapid signal inside the cabin, or when I use the brakes the lights will flash for a second then back down to just illuminated. Any ideas???
After reading my post I may have thought it maybe the other 2 remaining tail lights that are the two farthest lights on both driver and passenger side. But then it wouldn’t make sense, because they work perfectly fine with out the headlights on during the day.
LED's have a different (Lower) resistance than standard incandescent bulbs. For rear taillights, it's not typically a simple exchange between the two types of bulbs (no matter what the LED companies tell you). You usually have to install an additional resistor circuit for everything to work ok.
How is your current taillight configuration per side, 2 LED + 1 Incandescent? Try making it so that one side is incandescent and one side is LED. How's that affect the problem?
If the incandescent side is fine but the LED side keeps acting up, then you need a full LED kit and not just bulbs. If both sides work ok then you know you can't mix and match, you have to swap them all to LED or all to Incandescent.
I am using the Walmart bought Sylvania brand LEDs, everywhere, and I am having NO issues, except the
very DIM illumination, all but two of the LEDs at the back of the car, but they all go off after about 8
minutes. I am not even getting hyper-flash, everything works as it should, no battery drain.
They do NOT have lower resistance, they have a lower current draw. The lower in resistance you go,
the more current passes through. You mean HIGHER resistance, but that's still not the right term, it's
lower current draw. Current limiting resisters also add some resistance, so no, LEDs are not low
resistance, it would be higher, but it's not resistance at all, it's simple voltage drop across the LED.
LEDs do not use anywhere near the current bulbs do. LEDs are not resisters... The reason you get
erratic behavior with LED lighting is because the BCM/SBJ doesn't see the current load it should see with
regular bulbs. SO, you get odd lighting issues...
I originally had two outer tail lights in each, as LEDs, and one bulb on each inner, none of the tail LEDs
would stay on very dim after shut-down. Now they're ALL LEDs, and the inner two stay on, doesn't
bother me, they all go off after 8 minutes, including the center brake, and side markers. I will NEVER
use load resisters, because the whole idea in using LEDs is for lower current draw. If I cannot get
LED lighting to work without load resisters, then I will not use LEDs at all in the application. One of
my other cars had a bad light switch, when it got cold, the parking lights would turn on. Even with
regular bulbs, the car started up in the AM, but going to LEDs just made it easier...
LED's aren't best modeled as a pure resistor. LED's do have resistance, but often that's not the primary
concern when modeling a diode.
There is a good "approximation" which splits a diode into 3 discrete modes of operation.
If the voltage across the diode is greater than Vd, the diode behaves like a constant voltage drop (i.e. it will allow whatever current through to maintain V = Vd).
If the voltage is less than Vd but greater than the breakdown voltage Vbr, the diode doesn't conduct.
If the reverse bias voltage is above the breakdown voltage Vbr, the diode again becomes conducting, and will allow whatever current through to maintain V = Vbr.
LEDs do have resistance. It's small, but not insignificant. The resistance alone isn't enough to characterize their behavior, but to say that LEDs have no resistance
is a valid simplification only sometimes.
If you connect a raw diode directly to your battery without a resistor, the current in the diode is determined only by the (very small) resistance in the wiring and the
internal resistance of the battery, thus the current in the diode will be huge and it will (most likely) burn up, because the diode by itself offers no resistance but
conducts current. As LEDs get hotter, they draw more current, and will eventually burn up. This is why you use current limiting resisters, which will only allow
the LED to draw a limited current, which goes in series with LED power, now you have added resistance.
LOAD resisters are wired in parallel, and cause a DRAW on current, not a resistance in current. IF you put that same load resister in series with an LED, it
probably would not even light up, or be very dim, so now you have resistance. That is why they're called LOAD resisters, you wire it in like it was another
bulb.
LEDs have lower resistance. Your explanation of Load Resistors and the fact your have some bulbs that stay on just explained it.
An incandescent bulb is literally a resistor wire in glass bulb to protect the circuit. That's why some LED's will give off a little bit of glow when they are in a non LED circuit. The expected resistance normally posed in a circuit designed for an incandescent bulb is not present with LED so, some voltage and current will leak through and allow the circuit to work where an incandescent bulb would simply remain off because its resistance is what acts as the on/off switch. Overcome the resistance, the light bulb turns on.
LED also use less energy (draw less current) to achieve the same level of lumens as a standard incandescent bulbs because less energy is lost in other forms (i.e. Heat). Heat is the #1 energy loser with incandescent bulbs and that, combined with the amount of power needed to heat up that giant resistor to be bright is why regular bulbs are such energy wasters.
A Load resistor needs to be added to LED aftermarket bulbs in many cases when dealing with tail/brake/turn signal lights, so the circuit will work as expected by increasing the resistance and load (amperage) values back into the expected range. I already suggested that. Many, not all, people switch to LED's because they are brighter or have a more clean (white- aka cooler 3200K or above spectrum of) color vs incandescent yellow (3000K or below). It's got nothing to do with energy savings, thus they don't care about adding a load resistor.
A lot of LED companies have gotten wise to this and now will either incorporate an additional resistor circuit in their bulb or their wiring harnesses so it's not as much of an issue as it used to be. Doesn't mean it doesn't happen though, especially with cheaper ones that don't incorporate the extra resistor circuit.
That current is passing through the incandescent bulbs, it's just low enough so
those lights do not illuminate. Since LEDs use way WAY less power to light,
they are lit up because there is just enough there to light them. People complain
about it, but even with regular bulbs, that electricity is passing through the bulbs,
there just isn't enough to light them, but does light LEDs. This only happens till
the car goes to sleep, which is about 8 - 10 minutes, and has no effect on the
battery drain at that time.
An LED is not a resister, and doesn't have the same characteristics as a resister.
However, we are talking an LED bulb assembly, which probably has current limiting
resisters on it, so NOW is has resistance because there ARE resisters on the assembly.
A bare LED is not a resister.
I do it for energy savings, not what it looks like. As I said, if I have to use a LOAD resister
on one, I won't use it. That can still mean the bulb assembly has them built in, but
I check the current rating on the package.
The package has: 12V 1.7/.07W, So, that's .07 watts parking lights, and 1.7 watts brake and signal, so,
no load resisters in that assembly, and I didn't use any, and the brake and signals are fine.
The incandescent bulbs are 12.8/14V 27/8.3W, so 27 watts hi, and 8.3watts lo (parking).
So, say you put the 12V 6ohm load resister on your LED hi side, now your adding 25 watts to 1.7w for brake and
signal with an LED. You don't need the full 25 watts. When we put LEDs into cars at the shop, we use any
resister that will satisfy the blinker, or we put an electronic blinker. Some people don't even know what
load resisters to use, and don't realize they're using 50 watt units on their tail lights LEDs. You have to
make sure it's only 25 watts, and only goes on the hi element leads.
My '15 TSI is all controlled by the BCM. I have LEDs in all the lights. The arrows on the dashboard
hyperflash, but the outside lights do not, they blink at the normal rate. I also have no illumination anywhere
after shut down.
As I said, IF you need to use load resisters, you should only need to use them on two of the
bulbs, each one's HI side to satisfy the BCM or Blinker.
08-13-2018, 08:57 PM
Tail light problem :/
