You have some common GM truck stereo issues here. Here is how they are
repaired normally.

You *can* get backlight bulbs for the radio buttons at the GM dealer.
I don't know how they are sourced otherwise. They will be expensive,
according to an authorized Delco radio repair shop owner I talked to
last year.

The CD player isn't worth attempting to "diagnose". It probably either
doesn't power up, or displays an error message. You can get a
remanufactured CD player exchange either at a local Delco rebuilder
(cheapest best option) or at the Dealer (same thing but marked up) or
through places like Ebay which are expensive but require no exchange.
Used units are available on Ebay but I wouldn't think of going that
route. They want over $100 for an ungaranteed used player -- no
thanks!

Toyota MDT in MO