Ever since getting my 2005 GTP, The climate control lighting has been shoddy, 2 of the buttons you couldn't even see the icons on at night.
I decided to tear into it, and here is some details.
First pull the knobs off. I mean PULL them, don't rock them, don't pry them, eat your Wheaties and pull straight off. The potentiometers underneath have plastic shafts. Don't break them.
Then undo the screws in the back. There are 5 of them, and they are 3/16th hex heads.
Now lift off the face, and you see the bulbs. There are 7 of them, 4 of mine were burned out.
I figure if I'm gonna replace the bulbs, I might as well replace all 7. So I go and get online to order some and... $2.49 each? Oh heck no. But... You know whats costs $2.99? A two pack of LED flashlights.
The bulbs unsolder very easy from the underside. Make sure you save the blue rubber piece from the bulb on the "Cool" side of the temp knob.
Since I had to take an educated guess at the specs on these LEDS, I figured I needed about 330ohms of resistance for each one. Damn. Didn't have anything close on hand. Well how about resistors in parallel?
HAHAH, my methods are insane, but they work!
Note: Height IS an issue on some of the bulbs. You can safely go a few mm taller, but really not much, which is why I mounted them that way.
Now here is the money shot, which everyone will need, that I did all the legwork for you. The polarity! The standard bulbs need no polarity, and are also wired in parallel so if one burns out, the others still work. But LEDs are directional, and there is NO indicators on the board.
Plug it back in to test all the LEDs before you put it back together. I did ONE first and tested it before doing all the rest, and the one LED with the resistance I'm using (370ohm) looked no different then the stock bulbs to my eye, and with no hotspots. I actually used a blue LED for the "Cool" side of the temp knob and had to redo that one, as it was too bright. Which is why you need to save the blue rubber cover from that bulb.