LED Taillights Problem

[chasers36]

Originally Posted by wpoll

Not my image - borrowed it from another another BMW forum.

But if I recall correctly, yes, mine does look like this. It may be LCI specific - since the LCI makes MUCH more use of PWN in the lighting systems.

And in fact, LCI cars already use the brake lights as tails - from the factory. In fact, they don't even have any 5w tail lamps at all - they only use single filament 21W lamps in all positions in the rear, modulating them to be either tails or brakes as required.

So, basically, to my understanding, my model is a "pre facelift" and was simply not coded to use the brake lights as side lights, but the option is there, so it should be safe to attempt to turn that option on, but i can expect that to flicker like the upper taillight is currently doing.

[wpoll]

Originally Posted by chasers36

So, basically, to my understanding, my model is a "pre facelift" and was simply not coded to use the brake lights as side lights, but the option is there, so it should be safe to attempt to turn that option on, but i can expect that to flicker like the upper taillight is currently doing.

I guess so.. I've not goofed with a pre-LCI setup (as I don't own one) but it seems like that would be the result.

It also depends on a number of other unknowns - like how the LED tail lights are wired, how they internally current limit the LED forward current (series LEDs plus simple resistors most likely).

As Clavurion stated, adding some capacitors to smooth out the the PWM "signal" is a popular way to address the flicker.

[chasers36]

Originally Posted by wpoll

I guess so.. I've not goofed with a pre-LCI setup (as I don't own one) but it seems like that would be the result.

It also depends on a number of other unknowns - like how the LED tail lights are wired, how they internally current limit the LED forward current (series LEDs plus simple resistors most likely).

As Clavurion stated, adding some capacitors to smooth out the the PWM "signal" is a popular way to address the flicker.

Ok, so more fun issues have arisen lol I put capacitors on the taillights to stop the flickering, which was successful, but now I'm getting other check bulb messages, one for the license plate lamps, the side lights, and it says check high beams too. Checked the license plate lamps, they are now flickering, but the high beams seem fine and aren't flickering, and the side lights seems fine too, I'll double check for flickering, but what gives!?

[chasers36]

I did some more testing, and have not found a solution. With the capacitors installed, the flicker went away on the led taillights, but then started to cause a lot of random check bulb messages, my license plate lights started flickering, and it caused my turn signals to malfunction as well, they did the fast blinking thing. Pull the capacitor off, everything returns to normal, but the leds flicker. I guess I'll just live with it, but I'm still very curious as to the weird behavior after the capacitors were installed. They are 25V 6800uf ones, and are the correct ones from what i've been researching. Just really stumped. I'm not much of an electrician, so maybe someone can enlighten me to what is happening with the capacitors attached and all the weird other light behaviour.

[wpoll]

Weird... the caps should be only used across each circuit - so you would need four of them
- one on each of the tails (L+R) and one on each brake circuit (L+R).

The caps connect with the (-) on the common ground and the (+) on the tail or brake circuit.

I'm guessing you followed something like this: -

https://www.xoutpost.com/bmw-sav-for...nics-shop.html

[chasers36]

Originally Posted by wpoll

Weird... the caps should be only used across each circuit - so you would need four of them
- one on each of the tails (L+R) and one on each brake circuit (L+R).

The caps connect with the (-) on the common ground and the (+) on the tail or brake circuit.

I'm guessing you followed something like this: -

https://www.xoutpost.com/bmw-sav-for...nics-shop.html

I did make sure everything was wired correctly, just very strange behaviour. I'm just going to live with the slight flickering for now, I'll probably venture into upgrading my LCM III to a LCM IV at some point, for the extra coding options. Been researching on that, and looks like i'm ok to get any of the LCM IV options, just would need to do some coding to make sure it works correctly with the headlight vertical aim control module.

[chasers36]

Just posting an update on the LED tail lights situation, and my apologies for anyone that was waiting for my response.


I ended up going the resistor route instead of the capacitor route, and its been months now of no issues! Each led has its own resistor, and they are working great with no flickering, and no random bulb out messages or errors. I went with Philips 21W resistors, and found some brackets to mount them on, and they've been working great! Below is a link for the resistors.


https://www.amazon.com/PHILIPS-warni.../dp/B074P362V4


I'll maybe look at upgrading to an LCM4 for more functionality control for coding PWM and whatnot, but I'm satisfied with this solution for now.

[Homerlovesbeer]

Thanks for the update