middle brake light "half" broken

[upallnight]

Wow someone actually used the search to find a solution to a problem, instead of like so many noobs posting how can I fix this. Good job sir.

[Bmwe5320023.0]

So for me half the bar wouldn't light up.
I opened it up by cutting along with a dremel wheel.
I inspected for damage and didn't find anything too obvious.


I connected the led strip to the connector with the brake pedal applied and tried bridging different segments. I was able to find a point where all the diodes would light up except one, no matter what I tried.
So I soldered a piece of wire and now all of my diodes work except one.

I tried different variations for the last done, bridging both positive and negative to the diode, but it just won't light up.
In fact, if I try to provide the non working diode with power, the while segment turns off.
I tried to demonstrate it with the following 2 pictures.


If I provide positive voltage to the diode, it simply kills the whole segment with 4 diodes. If I disconnect the wire, 3 of the 4 diodes light back up.

Does this mean this single diode is dead no matter what?

[Bmwe5320023.0]

Well, one diode was burned out and was causing problems. You can see on the picture how dark it is.
Took it out and instead used a couple of diodes that I removed from a headlamp.
Soldered them in and now everything is working!

[crystalworks]

Nice work finding the problem. LEDs are SUPER cheap. They look like 5mm spider LEDs. I have a few hundred here on hand. You could order a handful and do it with the correct LED if you were so inclined. Looks like there are 2 series strands for the rear bar. Either way, nice work.

I can send you a few in an envelope if you want. PM me.

[Bmwe5320023.0]

Thanks buddy!
I'll leave it at that for now.


The bar is a little bit uneven but better than just half being lit. I sealed it off with gorilla clear adhesive so I don't want to take it apart again.
If it breaks again I will just get a unit from the scrap yard.
The time it took to fix it wasn't worth it but I just wanted to troubleshoot and learn lol
Hopefully this will help someone who doesn't live close to a scrap yard.

[oldskewel]

On my 2001, and I assume all of them, there are 24 LEDs wired in 6 parallel groups of 4. If any one LED fails, it will take out the group of 4, but other groups will stay lit. 12V powers the whole strip, and with that supplied (I used a cordless tool 12V battery for bench testing and repair), about 9.25V drops across each group of 4.

Not having spare LEDs, my solution was to first swap one of the end (#1 or #24, say #24 for this example) LEDs in place of the dead one. Doing only that would kill the entire #21-#24 cluster, which is an improvement, but still noticeable.

So I then did some calcs to find the right sized resistor to solder in place of the missing LED. This way, all lights are evenly illuminated, and missing a single LED on the very end of the strip is not noticeable. It would have been better if I had a spare LED of the right voltage and intensity, but I was glad to fix it without a trip to the store or waiting for a part.

BTW, before making this permanent fix, I was able to fix it temporarily (thinking it was permanent) just by reflowing the solder on the near-dead LED. Discussed in:
https://xoutpost.com/bmw-sav-forums/...ml#post1060746