Tail lights quick flash when unlocking, opening and closing any door

Phil123

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I have installed a pair of LED tail lights, and they do NOT hyperflash. However, when I unlock, open or close any door, the rear right light flashes for half a second (only the rear right). Super weird. Kinda looks like the car is letting go of some electricity through the light, or even static (why would it flash when closing a door ?). I tried another brand of LED tail lights and they do the same. I tried to reground from directly the light harness, still happens. I tried different resistors, still happens.

Anyone has an idea of why this is happening ? Thanks ! I am slightly going insane.
 
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How did you get them to not hyperflash in the first place? Also, what are they? Either link or at least describe the ones you have. In addition, what year jeep and trim level you have. There is different tech depending on the year.

At one point I tried LED bulbs in the stock tail lights but they would always hyperflash, as well as never being as bright. However, it has been a number of years now, so I'm curious why yours don't hyperflash.

Also, depending on the year of the jeep, they were just not built with LEDs in mind, so while in many cars you can just replace the flasher in the fuse box, in a wrangler, the flasher is not a removable part.
 
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@MacGuyver I don’t think you can just use a LED bulb, I believe you need to install a new light fixture which has the hardware for difference in voltage. I have heard that if all the bulbs are changed to LED that might work. There might be an option out their to replace the flasher to account for a LED bulb, not sure though.
 
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How did you get them to not hyperflash in the first place? Also, what are they? Either link or at least describe the ones you have. In addition, what year jeep and trim level you have. There is different tech depending on the year.

At one point I tried LED bulbs in the stock tail lights but they would always hyperflash, as well as never being as bright. However, it has been a number of years now, so I'm curious why yours don't hyperflash.

Also, depending on the year of the jeep, they were just not built with LEDs in mind, so while in many cars you can just replace the flasher in the fuse box, in a wrangler, the flasher is not a removable part.

I have a 2010 Sahara 3.8, Canadian version (Obligatory DRLs).

Here are both lights I purchased, tested and do the same flickering (FYI, they both come with built-in or attached resistors which is why they do not hyperflash) :

1. https://www.extremeterrain.com/raxiom-led-tail-lights-smoked-0717-jk.html
2. https://www.amazon.ca/dp/B081RGJSPC/?tag=tjforum-20

I've read that i could get some CANBUS LEDs that simply switch out with the bulbs (i think) but my OEM fixture broke which is why I wanted to switch to LEDs in the first place...
 
@MacGuyver I don’t think you can just use a LED bulb, I believe you need to install a new light fixture which has the hardware for difference in voltage. I have heard that if all the bulbs are changed to LED that might work. There might be an option out their to replace the flasher to account for a LED bulb, not sure though.
You can, but it doesn't work well. Meaning that Wranglers use a 3157 bulb and it is an extremely common bulb type, so they sell LED versions. However they hyperflash and the light pattern coming off them makes them dimmer in the OEM housing than the light pattern off a standard bulb.

In addition, what I was talking about in my first post is that it is impossible to replace the flasher in a wrangler. It is built into the circuit board in the dash. I looked into this in the past. The 2017 or 2018 may have a slightly different board as they could come with LED headlights as an option... However I doubt it.

@Phil123 One thing to know about the cheap LED lights you get from pretty much anywhere online (I have a set of cheap headlights so I'm not bashing them)
is that the reason they are cheap is the very limited shielding that gets put into them, in addition to the accuracy of resistance / voltage required, etc. It's the reason that the top names ones, along with any OEM are so ridiculously expensive.

With regards to what you are experiencing with the quick flash a few things come to mind as possibilities.

1. One of the reasons that standard bulbs seem to take longer to blink is because they fade in and out, where LEDs are almost instant on off. That could account for the very brief flash you are seeing.

2. I think the trailer connection is behind the left tail light.. and LEDs are strange. Because of their super low voltage requirement they can turn on or not turn on depending on how the little computer that controls them works. A standard bulb is nothing more than a resistor that glows, while an LED bulb is vastly more complicated. That trailer connection could be changing the voltage the smallest amount, but just enough to change how that sides LED functions.

3. An interesting test would be to temporarily switch the two rear lights and see if the same things happens. Obviously you wouldn't drive anywhere, but uninstall, then plug left into right and vice versa and watch to see what happens. It will at least eliminate either #2 or a strange malfunction in the light.

LEDs are strange.
 
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Thanks, I know they make LED bulbs, but you end up with the hyperflash (learned from my son’s experience). I guess that is what I meant by can’t just use a LED bulb, I should have been more clear. They are out there, but cause the hyper flash. I have heard that if all the bulbs are changed to LED that may eliminate the hyper flash, but don’t know.

Interesting on the flasher being part of the circuit board. I had mentioned it cause I thought I saw one company which stated the assembly / setup came with a new flasher to replace the existing one. But hey I was looking at a lot of LED’s so who knows. Ended up going with a brand called Raxiom from ET (Headlights) so far they have been working well and really like them over the stock. Picked them up on sale for $100, normally $160.
 
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Thanks, I know they make LED bulbs, but you end up with the hyperflash (learned from my son’s experience). I guess that is what I meant by can’t just use a LED bulb, I should have been more clear. They are out there, but cause the hyper flash. I have heard that if all the bulbs are changed to LED that may eliminate the hyper flash, but don’t know.

Interesting on the flasher being part of the circuit board. I had mentioned it cause I thought I saw one company which stated the assembly / setup came with a new flasher to replace the existing one. But hey I was looking at a lot of LED’s so who knows. Ended up going with a brand called Raxiom from ET (Headlights) so far they have been working well and really like them over the stock. Picked them up on sale for $100, normally $160.
Hmm... I suppose it's possible that switching all lights to LED could limit the hyperflashing... however it would mean that the flasher is highly controlled by the ECM. A typical replaceable flasher is a mechanical switch similar to a relay. The on / off switching is the sound you classically get when you activate your blinker. With the much lower resistance of LEDs the power that goes through the switch is increased causing it to hyperflash, or activate more often.

In a TJ they used the standard flasher that can be replaced. I'm unsure how common it is to have a separate flasher in any vehicle after 2007 when the JK came out. We all know how hesitant jeep have been to add new tech to wranglers until pretty much all other vehicles built practically have said new tech as standard. I'm fairly certain that most vehicles these days.. if not all... have to simulate the flasher sound as it is no longer a mechanical switch. I'm unsure where JKs flasher sits on that scale.
 
You can, but it doesn't work well. Meaning that Wranglers use a 3157 bulb and it is an extremely common bulb type, so they sell LED versions. However they hyperflash and the light pattern coming off them makes them dimmer in the OEM housing than the light pattern off a standard bulb.

In addition, what I was talking about in my first post is that it is impossible to replace the flasher in a wrangler. It is built into the circuit board in the dash. I looked into this in the past. The 2017 or 2018 may have a slightly different board as they could come with LED headlights as an option... However I doubt it.

@Phil123 One thing to know about the cheap LED lights you get from pretty much anywhere online (I have a set of cheap headlights so I'm not bashing them)
is that the reason they are cheap is the very limited shielding that gets put into them, in addition to the accuracy of resistance / voltage required, etc. It's the reason that the top names ones, along with any OEM are so ridiculously expensive.

With regards to what you are experiencing with the quick flash a few things come to mind as possibilities.

1. One of the reasons that standard bulbs seem to take longer to blink is because they fade in and out, where LEDs are almost instant on off. That could account for the very brief flash you are seeing.

2. I think the trailer connection is behind the left tail light.. and LEDs are strange. Because of their super low voltage requirement they can turn on or not turn on depending on how the little computer that controls them works. A standard bulb is nothing more than a resistor that glows, while an LED bulb is vastly more complicated. That trailer connection could be changing the voltage the smallest amount, but just enough to change how that sides LED functions.

3. An interesting test would be to temporarily switch the two rear lights and see if the same things happens. Obviously you wouldn't drive anywhere, but uninstall, then plug left into right and vice versa and watch to see what happens. It will at least eliminate either #2 or a strange malfunction in the light.

LEDs are strange.

So I switched them, and still the light in the rear passenger side quick flashes -- so the lights themselves are OK.
I disconnected all the lights i added out of the fuse box, and it still happens, so my headlights and fog lights aren't causing this issue...

How can I safely static proof that one light ? Blocking surges without overblocking so they still work ?
https://www.amazon.ca/dp/B081RGJSPC/?tag=tjforum-20
 
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So I switched them, and still the light in the rear passenger side quick flashes -- so the lights themselves are OK.
I disconnected all the lights i added out of the fuse box, and it still happens, so my headlights and fog lights aren't causing this issue...

How can I safely static proof that one light ? Blocking surges without overblocking so they still work ?
https://www.amazon.ca/dp/B081RGJSPC/?tag=tjforum-20
I did end up going down a bit of a rabbit hole, Sorry. A test you can do is just plug in the one and see what happens.

We probably should have mentioned that jeeps flash their lights when you lock or unlock. It is typically both tail lights as well. I believe that is what you are asking how to fix. My point in my overlong explanations, is that you may be stuck with the current functionality due to the differences in electrical draw by LED lights vs Standard bulbs.

If you didn't have the resistors in the tail lights they would probably both flash, but the blinkers would then hyperflash.

My guess is that the resistors is effecting the lock flash. This shouldn't be a problem beyond being a bit harder to find if you park next to a bunch of jeeps in a parking lot.

Is that your main concern? If you still have the OEM tail lights you can plug them in and double check that both lights still blink on lock, but as I said, I'm guessing there isn't really anything you can do. The Jeep is just doing it's best with tech that it wasn't designed for.
 
I did end up going down a bit of a rabbit hole, Sorry. A test you can do is just plug in the one and see what happens.

We probably should have mentioned that jeeps flash their lights when you lock or unlock. It is typically both tail lights as well. I believe that is what you are asking how to fix. My point in my overlong explanations, is that you may be stuck with the current functionality due to the differences in electrical draw by LED lights vs Standard bulbs.

If you didn't have the resistors in the tail lights they would probably both flash, but the blinkers would then hyperflash.

My guess is that the resistors is effecting the lock flash. This shouldn't be a problem beyond being a bit harder to find if you park next to a bunch of jeeps in a parking lot.

Is that your main concern? If you still have the OEM tail lights you can plug them in and double check that both lights still blink on lock, but as I said, I'm guessing there isn't really anything you can do. The Jeep is just doing it's best with tech that it wasn't designed for.

They do blink normally :) However, the passenger side tail light quick flashes before that normal lock/unlock blink -- i.e. I would press the unlock button on my key, the right tail light would quick flash once, then proceed to the normal 2 blinks with the left tail light (so right tail light would flash 3 times, and the left would flash the normal 2 times).

Also the right tail light quick flashes when I open or close a door.
 
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They do blink normally :) However, the passenger side tail light quick flashes before that normal lock/unlock blink -- i.e. I would press the unlock button on my key, the right tail light would quick flash once, then proceed to the normal 2 blinks with the left tail light (so right tail light would flash 3 times, and the left would flash the normal 2 times).

Also the right tail light quick flashes when I open or close a door.
Maybe it's part of the system that checks for blown light bulbs and fuses?

It's possible that this was always happening with the regular light bulbs but they may be slow enough to illuminate that it just wasn't visible. LEDs are so much faster at turning on and off.
 
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Maybe it's part of the system that checks for blown light bulbs and fuses?

It's possible that this was always happening with the regular light bulbs but they may be slow enough to illuminate that it just wasn't visible. LEDs are so much faster at turning on and off.
This fits my assumptions as well. The fact that switching the two lights led to the same effect implies to me that nothing odd is going on. I've contemplated rear LEDs, but never did it because I want that hyperflash if something fails. (It's by design to indicate a blown bulb if you were unaware)

I have LED fog lights as well that came with my headlights. Both sets have halos with the headlights able to integrate into the blinkers. The whole set of 4 cost me around $100. The electrical waveform feedback from the Fog Halos was so bad that if I turned them on, I would loose radio reception... and I hate satellite radio. So that part of my new lights got unplugged. I was going to use them as DRLs, now they are just dormant.

LEDs are not the same as standard bulbs, and do strange things when plugged into a machine not designed for them. I can only imagine that the $400 and up ones from the big companies take that stuff into account. With the cheap ones you are just rolling the dice. Hell, I had to re-arrange the wires for my headlights because two of them were in the incorrect socket.
 
I'm runniñg full on LED rears.
Audexen . Work really well with
resistor installed.
Had buddies behind me and lights
work really well.
But I do get brief flash when closing
rear gate . I don't think about as everything
else is at should be .
IMG_2320.PNG
 
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I'm runniñg full on LED rears.
Audexen . Work really well with
resistor installed.
Had buddies behind me and lights
work really well.
But I do get brief flash when closing
rear gate . I don't think about as everything
else is at should be .
View attachment 123972
Yeah, these are exactly the ones I am running right now, giving me this issue...

You'll notice, eventually, it blinks when you open and close any door -- and blinks when you unlock with the remote key.

Its kind of annoying, when you're trying to fix everything and then face something unrepairable ;)

Frustrating. Especially when it doesn't make any sense, why when closing a door lol.. urgh !!
 
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Yeah, these are exactly the ones I am running right now, giving me this issue...

You'll notice, eventually, it blinks when you open and close any door -- and blinks when you unlock with the remote key.

Its kind of annoying, when you're trying to fix everything and then face something unrepairable ;)

Frustrating. Especially when it doesn't make any sense, why when closing a door lol.. urgh !!
This fits with the LEDs are strange and require almost not power to activate, and in part, some of the idiosyncrasies of electrical systems.

For example, depending on how the circuit is wired, especially if it is parallel, an LED bulb can glow even when the circuit is turned off and the switch is off. It clearly isn't turned on, but there is a faint glow. I don't remember exactly the reason, but it very much fits my statement of LEDs are strange. This is most especially true when the electrical system isn't originally designed for it.

What you are probably seeing, is that there is a signal sent to the computer to say the door is closed, and because in a non LED system they didn't need to worry about noise in the system they don't have the electrical filters. (more stuff is more money) so what you get is a quick flash from the tail lights that are on a related circuit for when the doors are locked.

I'm just guessing with all that, but I'm probably not far off.
 
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Yeah, these are exactly the ones I am running right now, giving me this issue...

You'll notice, eventually, it blinks when you open and close any door -- and blinks when you unlock with the remote key.

Its kind of annoying, when you're trying to fix everything and then face something unrepairable ;)

Frustrating. Especially when it doesn't make any sense, why when closing a door lol.. urgh !!

Just went outside to double check things out .
When I lock via remote , all turn signals flash once , front & rear , horn honks once .
When I unlock same thing . All. turn signals flash once .
Headlights turn on for about 2 mins than turn off if vehicle not started . Horn doesn’t honk.
Had my GF stand behind the Jeep . No flashing when opening or closing any of the four doors . Only when closing rear gate .
Since we were going out to the Jeep for a moment somehow that turned into dinner out . Was sold to me “We are going out to the Jeep anyways”
So thanks for that . Lol

EDIT
Flashes once for locking
Turn signals front & back
Flashes TWICE when unlocking
Sorry about that . Was rushed
when typing last night
 
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