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In that type of circuit, the purpose of a resistor is to fool an old fashioned electromechanical flasher into working with an LED light that doesn't draw enough current to make the flasher work. That vintage flasher uses the current drawn by an old fashioned incandescent light bulb to make its flasher work. Adding a resistor in parallel with an LED bulb makes it draw more current so the old electromechanical flasher will work.

But a modern electronic flasher designed for LED lights no longer depends on current to make it flash so it works with LED bulbs without the resistor. :)
 
In that type of circuit, the purpose of a resistor is to fool an old fashioned electromechanical flasher into working with an LED light that doesn't draw enough current to make the flasher work. That vintage flasher uses the current drawn by an old fashioned incandescent light bulb to make its flasher work. Adding a resistor in parallel with an LED bulb makes it draw more current so the old electromechanical flasher will work. But a modern electronic flasher designed for LED lights no longer depends on current to make it flash so it works with LED bulbs without the resistor. :)
Awesome. Thank you. I didn't want to have to add a resistor so this is good news.
 
Are there differences in LED flashers??

I bought my TJ the Quadratec LED tail lights that come with the EP26 for Christmas. I also bought a LED bulb for the 3rd brake light. Installed it all and everything works perfect. I then decided to put LED in the front/side marker lights and front turn signal lights. Put in the front/side marker lights still everything works perfect. When I put in the front turn signal lights that things go a little crazy. When they are in the right turn signal on the instrument panel is illuminated, The odometer blinks when either turn signal is used and the front driver side turn signal illuminates when the brakes are applied. I have even tried putting the original bulbs back in the side marker lights and kept the turn signal with the LED and the same thing happens. Just curious if I might need a different LED flasher. Thanks!
 
Discussion starter · #24 · (Edited)
Awesome. Thank you. I didn't want to have to add a resistor so this is good news.
Are there differences in LED flashers??

I bought my TJ the Quadratec LED tail lights that come with the EP26 for Christmas. I also bought a LED bulb for the 3rd brake light. Installed it all and everything works perfect. I then decided to put LED in the front/side marker lights and front turn signal lights. Put in the front/side marker lights still everything works perfect. When I put in the front turn signal lights that things go a little crazy. When they are in the right turn signal on the instrument panel is illuminated, The odometer blinks when either turn signal is used and the front driver side turn signal illuminates when the brakes are applied. I have even tried putting the original bulbs back in the side marker lights and kept the turn signal with the LED and the same thing happens. Just curious if I might need a different LED flasher. Thanks!

There are two separate issues here. As Jerry B. mentioned a resistor used in the tail light/turn signal circuit is sometimes used to add resistance so that the stock flasher unit sees the proper amount of resistance and continues to blink at the normal pace. This is not a good way to accomplish this as it builds a lot of heat. You are better off going with a LED flasher.

The front lights are a different animal. The side marker lights in the fender flares have no dedicated ground and use a single filament bulb for both side marker and turn signal functions. I suggest you reread the second and third paragraph of the first post.

Here's the schematic of the way the front side marker/turn signal is wired.

Since the side marker/turn signal grounds through the front fender lamp filament, and it takes less voltage to operate the front lights if they are led, I think you are going to have issues until you add a dedicated ground to the side marker and use a double filament led bulb or the resistor mod mentioned in the first post which has nothing to do with the flasher, but is meant to give a single filament bulb partial voltage for the parking (side marker) light, and full voltage for the turn signal.
 

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There are two separate issues here. As Jerry B. mentioned a resistor used in the tail light/turn signal circuit is sometimes used to add resistance so that the stock flasher unit sees the proper amount of resistance and continues to blink at the normal pace. This is not a good way to accomplish this as it builds a lot of heat. You are better off going with a LED flasher. The front lights are a different animal. The side marker lights in the fender flares have no dedicated ground and use a single filament bulb for both side marker and turn signal functions. I suggest you reread the second and third paragraph of the first post. Here's the schematic of the way the front side marker/turn signal is wired. Since the side marker/turn signal grounds through the front fender lamp filament, and it takes less voltage to operate the front lights if they are led, I think you are going to have issues until you add a dedicated ground to the side marker and use a double filament led bulb or the resistor mod mentioned in the first post which has nothing to do with the flasher, but is meant to give a single filament bulb partial voltage for the parking (side marker) light, and full voltage for the turn signal.
Gotcha. I see what you are saying now. I may not mess with them then. Don't know much about wiring.
 
I can verify the LED side markers I converted a couple years ago work fine with the factory flasher my '04 came with. The LEDs work as running lights and flash with the turn signals as the factory wired the OE side markers to do. I made no wiring modifications, I just had to observe the LED wiring polarity.
 
you can buy the 3 wire LEDs from amazon for $10 a piece. They are the exact same lights that Metal Cloak sells. I put the LED flasher in and everything works great but since I have an '05 LJ, I get a constant beep when the parking lights are on, which I believe is due to the lack of resistance.
 
Hold on there Jerry the factory side markers have two flash modes one with park light on and other with park lights off

One in sync and other opposite sync with turn filaments all via a float ground and one mode current one way and other way current opposite way so no way I see a plain two wire single direction current flow led working same as factory markers

Two in parallel with opposite polarity would
 
I just put in a set i got on ebay for $8 per pair. They are 3 wire. Seem to work ok.
Very dim though.
And the blinking is almost unotivable with headlight on.
I have a 2 wire set as side markets from another company that are 10x brighter

Are the amazone or poison sypder 3 wires really bright?
 
I'm having a difficult time getting my LED turn signals and side markers to work properly. I made the pair of resistor/diode adaptors and have spliced then into the factory harness.

Lights off, left turn: all four LEDs flash in unison (sometimes left side has a quicker flash)
Lights off, right turn: all for LEDs flash in unison (sometimes left side has a quicker flash)

Lights on: all four LEDs steady on

Lights on, left turn: left flash in unison
Lights on, right turn: right flash in unison

I have an EP26 flasher relay. And a replacement multi function switch. Factory flares.

Putting in one factory turn signal bulb in will make the left/right sides flash separately. Though the turn signal and side marker lights will always flash in unison.

Both resisters read 0.55kohm
The diodes read between 0.625-641v and none are "leaking" backwards. Should the range in voltage be closer?

While I know it is fairly simple, this level of electrical is unfamiliar and confusing to me. Am I correct in thinking that I need more resistance when the lights are off?
 
Discussion starter · #31 ·
I'm having a difficult time getting my LED turn signals and side markers to work properly. I made the pair of resistor/diode adaptors and have spliced then into the factory harness.

Lights off, left turn: all four LEDs flash in unison (sometimes left side has a quicker flash)
Lights off, right turn: all for LEDs flash in unison (sometimes left side has a quicker flash)

Lights on: all four LEDs steady on

Lights on, left turn: left flash in unison
Lights on, right turn: right flash in unison

I have an EP26 flasher relay. And a replacement multi function switch. Factory flares.

Putting in one factory turn signal bulb in will make the left/right sides flash separately. Though the turn signal and side marker lights will always flash in unison.

Both resisters read 0.55kohm
The diodes read between 0.625-641v and none are "leaking" backwards. Should the range in voltage be closer?

While I know it is fairly simple, this level of electrical is unfamiliar and confusing to me. Am I correct in thinking that I need more resistance when the lights are off?
Not following exactly what you're attempting to do. You mentioned the resistor/diode mod, and also the stock lamp holder, and that you replaced the led with a stock bulb. I haven't tried the mod using a stock lamp holder/led bulb, but if that is what you're doing, I would guess that you would have to ground the wire that connects to - side of the led you're using in the holder, and connect the wire from the resistor/diode mod to the + wire.
 
... I would guess that you would have to ground the wire that connects to - side of the led you're using in the holder, and connect the wire from the resistor/diode mod to the + wire.

Correct. Stock lamp holders. I did run the negative to ground. Though I used the same ground as the turn signal, if that matters.

Something else I just noticed is that in the instances when all four LEDs flash, both rear lights flash as well.
 
Discussion starter · #34 ·
Correct. Stock lamp holders. I did run the negative to ground. Though I used the same ground as the turn signal, if that matters.

Something else I just noticed is that in the instances when all for LEDs flash, the rear lights flash as well.
Not sure...If you're sure your mods are wired right and everything is insulated, my guess would be a bad ground, bad mf switch, or flasher relay.
 
Not sure...If you're sure your mods are wired right and everything is insulated, my guess would be a bad ground, bad mf switch, or flasher relay.
I am confident in the mod. The more I think my way through this, the more I wonder if it is the new MFS from last year. I still have the factory flasher relay in a box. If I put it back in, then ordinarily I would just have hyper flash, correct?
 
Any difference if you pull the side marker light bulbs?
Headlights off, no side markers: both turn signals flash together. Sometimes the opposite side being signaled has the quick flash. This is inconsistent.

Headlights on, no side markers: turn signals function correctly.

Same behavior if I pull the turn signals and leave the side markers installed.
 
Discussion starter · #39 ·
Headlights off, no side markers: both turn signals flash together. Sometimes the opposite side being signaled has the quick flash. This is inconsistent.

Headlights on, no side markers: turn signals function correctly.

Same behavior if I pull the turn signals and leave the side markers installed.
Still sounds like a ground issue or mf switch to me.
 
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