I did the LED conversion in my 13 button OBC 2 weeks ago. I used two yellow 5mm LEDs with a 270 ohm resistor. I just picked up the LEDs at Radio Shack and they turned out to be too dim (apparently 1200mcd or less). Despite it being a pain in the ass, I went back in today and replaced the LEDs with ultra bright white LEDs that are 8000mcd. They were around 10 cents per LED. There are bright amber LEDs also but they were expensive and I figured white LEDs would be fine. 30 minutes later my OBC is perfect and with LEDs I won't be doing that job again any time soon. Very happy. Instructions I followed are below. Very easy to do and now if you read my post you can avoid doing it twice. ;-)
Maybe a little more information would be helpful. First, the right resistor appears to be around 300 ohms in order to run the LED at around 20mA. The circuit diagrams show that there are other resistors and loads on the circuit when headlights are on and when they are off, so keep that in mind. The right LED seems to be around 5000mcd. To my eye, 8000mcd looks a little bright and 1200mcd looks a little dim. The original lights are incandescent, which is hard to match to an LED. A yellow or amber LED will result in the backlight looking too orange to my eye. A white LED results in a backlight that is a little lighter than the surrounding lights. I went with white which is cheaper and easier to find. My LEDs were also around 3.2-3.6 volts and around 20 degree viewing angle. Viewing angle doesn't seem to be a big deal since the housing reflects light nicely. The LED does dim fairly well from 50% to 100%, below 50% it drops off quickly. Doesn't matter to me as I really just need on or off, but it dims fine.
Maybe a little more information would be helpful. First, the right resistor appears to be around 300 ohms in order to run the LED at around 20mA. The circuit diagrams show that there are other resistors and loads on the circuit when headlights are on and when they are off, so keep that in mind. The right LED seems to be around 5000mcd. To my eye, 8000mcd looks a little bright and 1200mcd looks a little dim. The original lights are incandescent, which is hard to match to an LED. A yellow or amber LED will result in the backlight looking too orange to my eye. A white LED results in a backlight that is a little lighter than the surrounding lights. I went with white which is cheaper and easier to find. My LEDs were also around 3.2-3.6 volts and around 20 degree viewing angle. Viewing angle doesn't seem to be a big deal since the housing reflects light nicely. The LED does dim fairly well from 50% to 100%, below 50% it drops off quickly. Doesn't matter to me as I really just need on or off, but it dims fine.