Replacement SMD LEDs for an older HO scale Athearn Genesis GP9 failed incandescent bulbs

We overview of my method of replacing incandescent bulbs in older Athearn Genesis models. This technique can be applied to many other diesel locomotives in HO scale. I used the Details West LN-341 headlight lens enhancement part along with pre-wired SMD 0402 LEDs.
Other projects on TH-cam that I've used this method with:
Burlington Northern SW-12
• Burlington Northern SW...

[@scotabot7826]

Wow Man, that headlight is so scale and realistic. So nice looking. A beautiful locomotive with a dim to so-so headlight just ruins the model in my humble opinion. You have knocked this one out of the park!!

[@blackhillsandeasternrailroad]

Thanks! Those SMD LEDs are highly directional, so it really is pretty easy. The light tends not to bleed out to the side like with incandescent bulbs. The trick is to get a color that everyone can agree on!

[@alanwbelcher]

I missed it. You put a resistor on the +14 pad on the board and soldered that to the LED lead. I assume that went to the red wire, but where did you connect the other wire lead?

[@blackhillsandeasternrailroad]

If I recall correctly, that is a GN-1000 board. Would be the pin right next to the +14 pad, on the front of the board. Ordinarily, that wire would be the white for F0F (front headlight) and the yellow wire would be the rear (F0R) on the other end of the decoder.