The back-lighting of the climate control LCD's and switches, in their stock form, are orange LED's, rather than incandescent bulbs like the dash LCD's. That will make this project much simpler as the supply voltage is already 1.5 volts, so no need for resistors. Just a matter of removing the old LED's and installing new ones.
I will not be doing a multi-color setup like I did with the dash lights
(see here), just to keep things simple. Blue is my favorite anyway,so we're going with blue for this project. The orange and blue really clash...
EDIT: I'm considering offering a retrofit with a core exchange. The core exchange kit would include these parts with the backlight color of your choice. You could also just send me these parts for a retrofit.
Any interest?