Turn signal LED not working with Sequential tail lights

04gtdrop · Aug 22, 2006

ok, so i bought some led's to replace my turn signal up front....they look good i think. nice and bright. but they are not working properly....

i have sequential turn signals and when i replaced my regular bulbs with these led's they started going way too fast.

When i put the hazard lights on with the led's they work just fine and go at the slow rate so that way they can sequence out.

But when the leds are in and i use my turn signal like normal, it speeds up and the Sequential turn signals dont work the right way. instead of all 3 bulbs on that side lighting up, only one will light up.

So the led's only work properly when the hazard lights are on.

i checked to make sure that they were in the right way, when i fliped them over and pluged them in the other way. they would not even light up.

so i swaped the leds out and put the regular stock bulb in and now my Sequential tail lights work fine.

Does anyone know why this is happening?

I had a similar problem to this a long time ago when my flasher was not plugged in all the way. but obviously it has something to do with these led's.

im wondering if its these specific bulbs, or is it just becuse they are led's???

Mike97gt · Aug 22, 2006

you may have better luck on mustangworld with this question. The only thing I can think of is that the resistance of the LED is to high it's acting almost like a open circuit ( blown bulb)

Red2000GT · Aug 22, 2006

Yeah,basically what svttech said. The led's don't "load" the flasher like normal bulbs so it speeds up and doesn't give the sequentials time to fully light up. You could try putting a resistor in line with the LED's to see if that helps. Try 200 ohms to start and go higher or lower from there depending on what happens. If it's too slow,use a lower resistance,too fast still,more resistance.

BigChiefSmokem · Aug 23, 2006

Red2000GT said:
Yeah,basically what svttech said. The led's don't "load" the flasher like normal bulbs so it speeds up and doesn't give the sequentials time to fully light up. You could try putting a resistor in line with the LED's to see if that helps. Try 200 ohms to start and go higher or lower from there depending on what happens. If it's too slow,use a lower resistance,too fast still,more resistance.

Exactly what he said. I bought LED turn signals off ebay and they werent any brighter than the stock bulbs and because the resistance was so low on them, they caused the car to think a bulb was out, thus speeding up the turn signal and causing my sequential tail lights to not go thru a full sequence. I took them out and did away with them, cause I didnt feel like wiring in a resisitor just to have LED turn signals.

n0v8or · Aug 23, 2006

IMO svttech76 has it right (as usual). The flasher includes a circuit that monitors the turn signal bulb current. When the current is too low, this is usually caused by a bad bulb. The flasher switches to a fast mode to warn you to check your turn signal bulbs.
Your LEDs use less current than a bulb, so trigger the circuit.

Other than forgetting about the LEDs, I can think of 2 possible solutions:
(1) Modify the flasher to eliminate the bulb current monitor. StangNet member GT-03 is the expert on the internal flasher circuit and how to modify it.
(2) Add resistance in parallel with each front turn signal to increase the (apparent) bulb current. For example, addition of a 15 ohm resistor on each side would increase the current by ~1 amp, which might be enough. The downside is you will need 20 watt resistors (big and ugly).
Personally, if I felt that strongly about keeping the LEDs, I would go for option 1.

GT-03 · Aug 23, 2006

n0v8or said:
(1) Modify the flasher to eliminate the bulb current monitor. StangNet member GT-03 is the expert on the internal flasher circuit and how to modify it.

I would try replacing the stock flasher with one P/N F67B-13350-BA. That replacement flasher supports having one less incandescent bulb per vehicle side, which is kind-of what you have when you replaced one bulb with an LED.

04gtdrop · Aug 23, 2006

hmm ok, all good posts! thanks a bunch.

But the stock flasher was already replaced with a special one that was mod'd to make it work correctly.

so how hard would it be to add in a resistor?

or how hard would it be to open up this flasher and mod it?

Wow, i didnt think i was going to get an answer just becuase it seems like an odd question.

But ya'll on SN came through again. Atleast now, I know why its doing that.

Does anyone know if they make an LED that has a higher ressitance, or is that pretty much how ALL LED's are?

GT-03 · Aug 23, 2006

04gtdrop said:
or how hard would it be to open up this flasher and mod it?

Does anyone know if they make an LED that has a higher resistance, or is that pretty much how ALL LED's are?

It isn't all that difficult to open up the flasher. However, mod'ing it isn't all that straight forward. The "resistor" which is used to measure current flow, and therefore detect if a bulb is burnt out, is really just a hunk of carefully machined metal. So, you can't just go down to RS and buy one of a different value.

The other possibility is to change out one of the real resistors. The resistor I have in mind, is the resistor which sets the flash rate. The flasher would still be in "error mode", but you could reduce the "error mode" flash rate to be closer to normal.

Did you just use plain old LEDs? They make replacement auto "bulbs" which are actually LEDs. Did you use one of those? Those already take into account an electronic flasher's current draw requirements, and should not affect flash rate (should not cause "error mode").

mity2 · Aug 23, 2006

use muti meter, measure the resistance on incondicent(SP?) bulb that was there. and run to redioshack, and get what ever resister that comes that value.

I've also seen people who installed dummy light bulb away from where you can see(like inside of trunk) as a resister, and got LED light(turn signal) to work

04gtdrop · Aug 23, 2006

GT-03 said:
It isn't all that difficult to open up the flasher. However, mod'ing it isn't all that straight forward. The "resistor" which is used to measure current flow, and therefore detect if a bulb is burnt out, is really just a hunk of carefully machined metal. So, you can't just go down to RS and buy one of a different value.

The other possibility is to change out one of the real resistors. The resistor I have in mind, is the resistor which sets the flash rate. The flasher would still be in "error mode", but you could reduce the "error mode" flash rate to be closer to normal.

Did you just use plain old LEDs? They make replacement auto "bulbs" which are actually LEDs. Did you use one of those? Those already take into account an electronic flasher's current draw requirements, and should not affect flash rate (should not cause "error mode").

well here is exactly what I bought

http://cgi.ebay.com/ebaymotors/2-AM...goryZ33713QQihZ019QQitemZ8071252493QQtcZphoto

so where is this other resistor? the real one that i would be able to change out?

I would realyl like to be able to put the led's back in and have them work with tai llights.

thanks

04gtdrop · Aug 23, 2006

ahhh crap, I think i just found a solution...man i feel dumb!

the seller that sold me the LEDS also sells a "load resistor kit"

http://cgi.ebay.com/ebaymotors/LED-...emQQcategoryZ33713QQitemZ8044304184QQtcZphoto

will this fix my problem? it sounds like it will, what do you guys think?

will it be hard to install....

man i feel like an idiot

Saleen4971 · Aug 24, 2006

mity2 said:
use muti meter, measure the resistance on incondicent(SP?) bulb that was there. and run to redioshack, and get what ever resister that comes that value.

so you know, you cant measure the resistance of a bulb with a meter. you have to measure the votlage and current, and use math to calculate the resistance. thsi is because teh resistanceof the bulb at rest, is different than it is when its on, which varies with temperature.

GT-03 · Aug 24, 2006

04gtdrop said:
ahhh crap, I think i just found a solution...man i feel dumb!

the seller that sold me the LEDS also sells a "load resistor kit"

http://cgi.ebay.com/ebaymotors/LED-...emQQcategoryZ33713QQitemZ8044304184QQtcZphoto

He also sells...

3 PIN ELECTRONIC LED FLASHER BLINKER FIX

So, it does appear that they realize that these LED's do cause problems.

04gtdrop · Aug 24, 2006

hehe, guess its a known problem...well it looks like i have found my solution.

Next step is when they get here, figure out how to install them.

Turn signal LED not working with Sequential tail lights

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I like Pro3 and all I got was this crappy CT.

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