Hi all,
Other day I noticed the LED bars on my back right tail light were not working, after pricing up replacements I thought I would introduce it to Mr.Dremel.
The two side marker LED's still worked but the bars did not, I reverse engineered the PCB and did some testing.
It appears the 2 side marker LED's are ran from a vehicle 12/14v > 12v Regulator > 560ohm resistor > 2x Side marker LED's in Series.
The 3 BAR/Parking light LED's run in series as well but differently. They are 12/14v > 12v Regulator > Generic 4001 constant current LED driver > 3x LED's in series.
Then there are some caps and a schottky diode for the current sense for the LCM/Bulb out error.
Managed to kill one of the side marker LED's during testing as I discovered the fault being the first LED in the series that make up the 3 Parking Light Bars.
Ended up replacing the 4001 LED Driver. (It popped the 2 side marker LED's after I moved them)
Then replaced both side marker LED's with 3mm 7600mcd RED with clear lens LED's.
As well as also replaced the first LED in the series for the light bars with a 5mm 9600mcd RED with clear lens
Here are some photos I put together, I can't include the 6th photo of the cut/plastic welding it back together due to 5picture per post limit.
Photos:
Photo1: PCB Diagram I put together.
x3 light01.jpg
Photo2: Top of PCB with original LED's
Old.jpg
Photo3: Top of PCB with new side marker 3mm & top LED bar 5mm installed.
New00.jpg
Photo4: Powered up & working with the new 4001 driver also soldered on.
New01.jpg
Photo5: Tail light back together and working as intended.
Working01.jpg
Cheers
Mat
Originally Posted by hakhawkOriginally Posted by geargrinder
I had to do this on my brothers e39 Celis lights. I’ll have to keep this handy good info thank you !
Me E30 87/ 325i + F25 12/ M-Sport + E32 94/ 740i
G/F’s E34 92/ 525iT + F48 18/ X1
Thanks Hozy,
I had the same issue as you, but was doing the job for a friend. He advised that all the LEDs were broken so i assumed it was the driver. After replacing the driver i found that only the 2 centre LEDS came on and not the light bar LEDs. It turned out that was the original problem not the whole light :|
So after a quick look I saw that the 1st LED in the series of 3 looked a little brown so replaced it and boom, all 3 started working. So my issue was one dead LED causing the light bars not to work. The LED on the end closest to the 4001 driver. Was a $4 fix vs $900 from BMW.
Hey, great post - and really helps with my issue too, I'm just ordering some replacement LED's and driver so I only need to make the change once - do you have a link to the LED's you got, I'm working up an order on farnell and want to make sure I'm ordering similar spec
Yep you need to cut open the abs plastic behind the 2 side marker leds on the tail light. A dremel is probably the tidiest way to achieve it. I have just gained access to the pcb board and yet to replace the failed led on my X3. I found that it was the first led that failed in the series, confirmed by shorting accross the pins of the first led which caused the 2 remaining leds to light up. Will pick up the led suggested from hozy from local electronic geek store tomorrow. Thanks again for your original post hozy, - saved me a bundle of cash!
a better photo, couldnt find my dremmel so used a multitool, worked just as well. Shows clearly where the PCB is. Unfortunately must have caught the LED on the way out and lifted the solder pad off the PCB. In the process of a make shift job but I reckon it may be something else causing the fault.IMG_20190416_165325.jpgIMG_20190416_165329.jpg
Just wanted to say a quick thanks to the OP. I searched far and wide to get end up with this thread. No one else had taken the time to document so it was very much appreciated. I was in the same situation with the first LED failed. Was a bit of a faff to swap and fiddly as electronics not my thing. However I got there in the end. Also thanks to the person who suggested shorting the LED to see which one was faulty.
Saved a fortune as these parts get more difficult to get hold of.
Cheers.
you can buy repair pcb board here https://xenons4u.co.uk/bmw-x3-f25-le...-b0038092.html will save you guys a fortune!
That's for the f25 not the e83 they are different pcbs.
did you have any luck on the tailgate? mind is out, does not look like i can use this process.
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