I am not sure if anyone on here has done this yet so I just wanted to post pix. I took apart the AC button and soldered a blue 3mm LED in place of the green one. It's easier to cut the LED and solder on a new one than to desolder it from the board. No resistor needed for the AC button. Then I took the socket bulb that lights up the rear defroster and put a 3mm LED and resistor in it.

The end result looks pretty good. The AC button is brighter because it's more direct on than the defrost button where the LED points downward. I'm thinking of replacing it with a red LED and bending the LED to point toward the button face.



I used UV, blue, and red on my NSX.

 

How about sanding the LED flat?

Looks good!