LED Tail lamps flickering

[Cheeky_Chris]

Hi guys,

I’m after a bit of advice. I’ve had autobeam rear LED tail lights in my car for just under a year, and unfortunately the other day one of them died. Promptly autobeam got me 2 replacement bulbs, but now they flicker intermittently. What’s especially weird is that they only flicker when the engine is running. I’ve had both my battery and alternator tested and there’s no issue there. They also don’t flicker when the brake is applied.
I’m stumped. Could I need some resistors? If so, which ones? Why are these bulbs doing it but the other LEDs didn’t?

Literally tearing my hair out with this!

 

[danbfree]

I have the same issue with red LED brake lights, mine happen to be ones that also strobe when pressing the brake but they too indeed flicker while engine is running... Have you done any headlight mods?

 

[Informacion]

I've seen my rear bulbs do this on start up once or twice. But never permanently. I actually think I have the same ones dan has. I could be mistaken though. https://www.amazon.com/gp/aw/d/B07KWR9D9C?psc=1&ref=ppx_pop_mob_b_asin_title

 

[Cheeky_Chris]

I have the same issue with red LED brake lights, mine happen to be ones that also strobe when pressing the brake but they too indeed flicker while engine is running... Have you done any headlight mods?

Yes I have. Nothing different from when I had the old LEDs in though. All my bulbs are from autobeam bar the turn signals


Sent from my iPhone using Tapatalk

 

[Cheeky_Chris]

I've seen my rear bulbs do this on start up once or twice. But never permanently. I actually think I have the same ones dan has. I could be mistaken though. https://www.amazon.com/gp/aw/d/B07KWR9D9C?psc=1&ref=ppx_pop_mob_b_asin_title

Yeah mine do it all the time but it’s not a consistent flicker. Sometimes it’ll stop for a couple of secs, sometimes it’ll stop for 10 seconds then start again. It’s so weird


Sent from my iPhone using Tapatalk

 

[danbfree]

Yes I have. Nothing different from when I had the old LEDs in though. All my bulbs are from autobeam bar the turn signals

OK, so from what I've seen,some LED headlight bulbs do this, for some reason adds flicker to the tail lights, I would love to figure this out as well if possible, but I now have the same headlights as you, but the Euro reverse cutoff, of course, so it could be the Euro headlight design is more prone to creating flicker on other LED's installed at the same time, but maybe some LED brake lights are more prone to just doing it regardless of headlights, but mine seems to change a bit based on the quality of the wiring connection I messed up a bit... do your headlight DRL's also flicker at all?

 

[danbfree]

I've seen my rear bulbs do this on start up once or twice. But never permanently. I actually think I have the same ones dan has. I could be mistaken though. https://www.amazon.com/gp/aw/d/B07KWR9D9C?psc=1&ref=ppx_pop_mob_b_asin_title

Yep, those are them, and mine seem to flicker all the time now that I have a kind of screwed up wiring connection to my driver side Euro headlight and now my LED DRL's on my Depo Euro headlights also flicker sometimes...

 

[Cheeky_Chris]

OK, so from what I've seen,some LED headlight bulbs do this, for some reason adds flicker to the tail lights, I would love to figure this out as well if possible, but I now have the same headlights as you, but the Euro reverse cutoff, of course, so it could be the Euro headlight design is more prone to creating flicker on other LED's installed at the same time, but maybe some LED brake lights are more prone to just doing it regardless of headlights, but mine seems to change a bit based on the quality of the wiring connection I messed up a bit... do your headlight DRL's also flicker at all?

Nah my DRLs are absolutely fine. Then again my car is UK spec. First time any of my LEDs has done anything like this however


Sent from my iPhone using Tapatalk

 

[Intuit]

Isolate your bulbs. Then add each of the variables back, one by one.
First, kill the engine and see whether the issue ceases on battery voltage alone.
Does the issue only exist if the voltage is raised beyond normal battery voltage? (note: no easy way elevate to 14v on battery)
Second, remove the bulb and power it directly; see whether the issue persists. (may get hot - do not hold by hand)
Third, reinstall the bulb in the socket, power it through the tail module's wire harness.
Fourth, power the bulb further down the harness... such as at the relay. (look at circuit diagram in *service* (not owner) manual before attempting)

LEDs are particularly sensitive to power fluctuations because unlike filament lights, there's relatively little delay, from the time that they loose power, to the time that they actually quit producing usable light. Filament lights spend a considerable time cooling down. (origins of the "brown out" phrase)

The flickering pattern leads me to suspect poor connection... which may be solder joints. Instead of all LEDs dimming, it could be that a panel or even individual LEDs are rapidly de/activating. One of my headlights does similar but only when initially activated for a minute.

 

[Cheeky_Chris]

Isolate your bulbs. Then add each of the variables back, one by one.
First, kill the engine and see whether the issue ceases on battery voltage alone.
Does the issue only exist if the voltage is raised beyond normal battery voltage? (note: no easy way elevate to 14v on battery)
Second, remove the bulb and power it directly; see whether the issue persists. (may get hot - do not hold by hand)
Third, reinstall the bulb in the socket, power it through the tail module's wire harness.
Fourth, power the bulb further down the harness... such as at the relay. (look at circuit diagram in *service* (not owner) manual before attempting)

LEDs are particularly sensitive to power fluctuations because unlike filament lights, there's relatively little delay, from the time that they loose power, to the time that they actually quit producing usable light. Filament lights spend a considerable time cooling down. (origins of the "brown out" phrase)

The flickering pattern leads me to suspect poor connection... which may be solder joints. Instead of all LEDs dimming, it could be that a panel or even individual LEDs are rapidly de/activating. One of my headlights does similar but only when initially activated for a minute.

So do you think it’s an issue with the LEDs rather than the car? I’ve gotten some resistors in the meantime, do you think they would help?


Sent from my iPhone using Tapatalk

 

[Intuit]

That's what the tests will help determine. Particularly for lights with fans, it's not unusual for LEDs to experience flickering. Have only one that's flickering or one is flickering more than the other, swap them to the other side. Does the behavior move with the diode?