Done it myself. However in my case I had to do it twice as there was another issue.
First replace was a generic diode from "Stock" (Box of assorted diodes) joy was not mine as it was short lived.
2nd try I measured the series resistor.. Way too small. so I got a JUMBO LED from Radio Shack, this is a high-brightness, higher current unit, and it required I ream out the hole in the reflector a bit.
I also did the math based on 14 volts and pickd a new resistor (From stock, box of assorted again) to put in.. Here is the math.. Forward current in mA/12 (Answer is in K-ohms, I got 0.6 as I recall or 600 ohms) if you like you can use Current in Amps'/12.
(Gives direct value, use next LARGER standard resistor)
That's all there is to it.
De-solder original resistor and replace (If necessary)
De solder original LED and temp insert new one (DO NOT SOLDER
Apply power, if it does not light reverse diode and try again, When it lights, Solder.
Home is where I park it!