Replace Individual LEDs in Tail Lights

[heinzboehmer]

Great video thank you. In his video the LEDs had 2 pads. One positive and one ground. These have 4 pads. Do I just test each pad until I find the positive one? Will the led still light up on me like that when only 1 ground is connected from the multimeter?

Yup the three grounds are all electrically connected, so it'll still light up even if your probe is only on one of them. Just mess around with all the positive combinations of the two probes on the four pads until you find the ones that work.

[SteelGreyM]

Like this: https://www.youtube.com/watch?v=AfgT3xhpRHM

Great video thank you. In his video the LEDs had 2 pads. One positive and one ground. These have 4 pads. Do I just test each pad until I find the positive one? Will the led still light up on me like that when only 1 ground is connected from the multimeter?

[heinzboehmer]

Hey,

I’m an electrical idiot. How would I go about testing with a multi meter? Do I need power to use it?

Like this: https://www.youtube.com/watch?v=AfgT3xhpRHM

[SteelGreyM]

You can test them with a multimeter. Three of the legs are ground and the other is positive.

When installing, find the three corresponding pads connected to the same trace on the circuit board. Those are the grounds.

Hey,

I’m an electrical idiot. How would I go about testing with a multi meter? Do I need power to use it?

[heinzboehmer]

You can test them with a multimeter. Three of the legs are ground and the other is positive.

When installing, find the three corresponding pads connected to the same trace on the circuit board. Those are the grounds.

[SteelGreyM]

I tried this but it didn’t work. I didn’t realize the LEDs were directional. How do you determine which direction each LED should go?

[netcsk]

Nice! If mine ever fail again I'm definitely going back and doing this with solder paste. I used a regular iron because I didn't have any on hand and was really just experimenting with it. So far mine have been just fine, but agreed, solder paste is the way to go!

It was in no way a knock to you. In reality I'm impressed that you were able to do it with an iron as I don't think I could have at all. Glad to hear it is holding up. Thanks again for the DIY!

[heinzboehmer]

Nice! If mine ever fail again I'm definitely going back and doing this with solder paste. I used a regular iron because I didn't have any on hand and was really just experimenting with it. So far mine have been just fine, but agreed, solder paste is the way to go!

[netcsk]

Some pictures (click for full size) and hints from my repair today.

First, thanks to the OP for doing the legwork on finding the right LEDs and making the DIY! I never would have attempted this otherwise.

I recommend cutting on the green line from this picture. I hit the board in one spot from cutting too close (got amazingly lucky I didn't damage a trace or LED). I also cut too deep along the outside and cut the bracket that holds the side marker LED. Disassemble by removing the T10 bolts.



I tested LEDs using the diode function on my multimeter


I had 3 LEDs out but only one was the cause. It was visibly burnt. I cut it off with an exacto knife and used solder paste and a heat gun to attach a new one. It was remarkably the easiest part of this and was my first time using solder paste. It worked incredibly well. Personally, I would not try this with typical solder and an iron considering the four pads for attachment.
Here's the solder paste I used. It's more than you'd ever need, even if you did all of the LEDs.
https://www.amazon.com/dp/B017RSZFQQ..._saYjFbMD6C2RQ



Tested before reassembly and it matched perfectly!

Brakes


I then reassembled, using double sided tape for the side marker light since I destroyed the bracket cutting.
Used butyl tape from home depot to seal the cuts.



Here's the bracket you dont want to cut and the size of these tiny LEDs.

[heinzboehmer]

On another note, I understand the messy soldering now that I see the new LEDs ha. Thanks again.

Lol yeah, a hot air reflow station would have been ideal, but I didn't have access to one at the time. Without one, it's hard to do a decent soldering job.

[netcsk]

Ah that's annoying. When I did this, I ordered a bunch of each because they were so cheap. I'm almost completely sure the right type is common anode because that's what I wrote down in the original M3Forum DIY, but you could be able to confirm this if you're going to open up your taillight anyway! The diode test function my multimeter was enough to light up the LEDs dimly, so I just went and probed a known good LED on the taillight to determine which of the four lugs were positive and which were negative. then did the same for the LEDs I ordered.

Excellent suggestion. I'll order the common anode versions and check before installing.

On another note, I understand the messy soldering now that I see the new LEDs ha. Thanks again.

[heinzboehmer]

Well poo, the wrong ones showed up in the mail today. At least it was only a <$10 loss.
Thanks for the DIY!

Ah that's annoying. When I did this, I ordered a bunch of each because they were so cheap. I'm almost completely sure the right type is common anode because that's what I wrote down in the original M3Forum DIY, but you could be able to confirm this if you're going to open up your taillight anyway! The diode test function my multimeter was enough to light up the LEDs dimly, so I just went and probed a known good LED on the taillight to determine which of the four lugs were positive and which were negative. then did the same for the LEDs I ordered.

[netcsk]

Red, common anode.

Well poo, the wrong ones showed up in the mail today. At least it was only a <$10 loss.
Thanks for the DIY!

[rbg]

I linked to it in the first paragraph, but here's the direct link in case that doesn't work:

https://www.oznium.com/loose-component-leds/plcc-4

Thank you did not see "Here" was a link :-)

[heinzboehmer]

Common cathode, red version?

Red, common anode.