Identifying correct LED replacement

[AZ_G]

Hello, brand new to the forum and glad to be here!

I am in the process of changing the interior lighting in my vehicle to LED's from incandescent bulbs. The LED's I'm installing are 6k color temp while the incandescent bulbs being replaced are your typical ~2.7k. Almost all of the bulbs are incandescent (map lights, dome light, visor lights, glove box etc.) with the exception of two lights that are used in the middle row foot well. Those (to my surprise) are LED's. However they are ~2.7k color temp to match the rest of the vehicle so I'd like the swap them out for 6k's so everything will match when I'm finished. I was able to disassemble and remove the PCB from the lower backside of the front seat where it is mounted and the board is fairly simple. I un-soldered the LED from the PCB and I don't see any identifying markings on it. Since there are no markings I guess I'll need to take some measurements and find a suitable replacement? I left one of the PCB's connected to the vehicle so I can use my meter to take measurements on it. I'm hoping you all can tell me what measurements I need to take in order to determine the correct LED to buy.

 

[Harald Kapp]

I'm hoping you all can tell me what measurements I need to take in order to determine the correct LED to buy.

No need to measure. The reistor reads 751 which is 750 Ω. A white LED has a pass voltage of approx. 3 V (you could measure that across the LED to verify the specific value of this LED). This makes for an LED current of approx. I_LED = (12 V - 3 V) / 750 Ω = 12 mA.
What you need is an LED in the same case as the old one suitable for a current in the range 10 mA ... 20 mA (if higher it won't hurt). And of course with your favorite color temperature.
Note the polarity of the LED when mounting it on the PCB. You will often find a polarity indicator on the back of the LED case.

 

[AZ_G]

Thank you Harald. I didn't realize that the housing color of the LED indicated an approximate voltage. Do you have any suggestions on where to purchase from? I'm looking at available options from distributors such as Digikey & Arrow and trying to narrow the choices but the list is quite long.

 

[Harald Kapp]

These should be available from a wide range of suppliers. Getting one or two from the ones you named could be costly as shipping costs are comparatively high.
Where are you located? Maybe a local dealer?
Where did you get your other LEDs from? Buy there or salvage bare LEDs from a surplus LED light with matching color temp.

 

[Audioguru]

Many colored LEDs are in a clear housing that has no color. A white LED usually has a yellow phosphor on top of the LED that looks yellow when it is not turned on.

 

[bertus]

Hello,

What is the size of the led?

There are many leds around:
white smd led

Bertus

 

[AZ_G]

Thanks everyone! @bertus I'm measuring ~3mm so it looks like a 3528 to me. These appear to be very common for automotive applications. These look about right and the specs say rated for 20mA. https://www.oznium.com/loose-component-leds/plcc-2

 

[AZ_G]

I ordered the LED's linked in my previous post and they are working perfectly. Thank you all very much for your help, especially that handy chart @bertus !