I just cut-n-paste the forums
I finally got some time to pull out the HVAC control module and replace the backlight behind the defroster button. The project was not to bad at all. However, I will warn you that the light bulbs are soldered in and not screw in.
Once you pull out the HVAC control module, pull out on the two knobs used for setting the temp - they are on pretty good, but keep pulling straight out and they will come. Then there are qty 4 3/16" screws that will need to come out (I used a nut driver) that holds the case together.
Once you open it up, you will see two green boards connected via a wiring harness, you do not need to disconnect the harness. All of the bulbs are covered with a blue/green cover - pull the cover off of the bulb you want to replace. Be careful though, you will need to reuse it.
Once the cover is off, heat up the solder joints used to hold the bulb to the board while gently pulling the bulb out. Reverse the process to install the new bulb. I used RadioShack part number 272-1154 as the replacement bulb and it matches the existing bulbs pretty dam close, if not dead on.
Go out to the truck and plug the harness back in and make sure everything works. Once it does, put the bulb cover back on, screw it together and rock and roll!
Here are the specs on the bulb I used as a replacement:
Voltage: 12volt
Current: 50mA
Light Output: 0.12MSCP
Bulb Type: T-1
Good Luck!
Note: verify the bulb to make sure it's at least close to what is described here

BEFORE any cutting is done.