Super easy change. I had to change those lights before. The lights just pop out the back. I'll see if I can find the part #s and the instructions to get to the bulbs.
Here is how to get to the bulbs. It only takes about 10 min.
How to Remove the Navigation Head Unit from a 2003 Toyota 4Runner[/QUOTE
And here is a link to more instructions and part #s, you can get the bulbs at the dealership for about $5. Gte extra just h=to have them.
http://www.toyota-4runner.org/problems-warranty-issues/6782-backlight-info-panel-flickering-5.html