It is a lot of work to get it out. Not impossible though. Here is a quick writeup someone made for a 2000 Silverado. It is slightly different, but for the most part the same. Here it is just to give you an idea.
"Have the A/C discharged.
Properly disable the airbags/theftlock for your safety.
Remove the main bezel surround, it just snaps out.
Remove and unplug the radio and AC controls by depressing the tabs on the sides.
Remove the snap on covers on either side of the dash (the ones w/ fuses and wires behind them).
Remove the trim under the steering wheel where your knees go. (2 7mm and some snaps).
Remove the metal steering column guard (4 10mm nuts)
Remove the pillar trims, they just snap out.
Remove the dash top by unscrewing the philips screws on the sides and the several 7mm under the dash bezel you removed.
Remove the air vents and then the extensions on either side of the passenger airbag. They pop out.
Remove the grab handle by pressing the white tabs you can see where the air vent extension was.
Reach in the radio slot and twist the light sensor to remove it.
Check for any other bolts, then pull the dash top straight back toward you to disengage the clips, then lift it up and out.
Open the glove box and remove the several bolt-head screws. There are more toward the middle where the fold-out cup holder was on the early models. When you have all the bolts out, there are several clips to disengage to remove the whole assembly. Unplug the cigarette lighters and ashtray light.
Now, remove the 4 10mm bolts close to the windshield that hold the dash and support in place and unplug the small harness and ground wire next to the right-most bolt.
Remove the kick panel near the passenger side door and unplug the huge wiring harness underneath. Unplug the 4 connectors up a little higher as well.
In the engine compartment, remove the heater core hoses and 13mm A/C evap hoses. Protect the A/C hoses, moisture will mess up your system.
Now, remove the 7 nuts/bolts in the engine compartment that are holding the AC/heater assembly in place. They start behind the intake manifold and go almost to the fender. The bolts have a black piece of rubber behind them, and the nuts have a green piece of rubber behind them. 2 are behind the drier/accumulator thing. Remove the evap drain tube extension.
To the right of the gas pedal, remove the trim piece and unbolt the vertical dash support from the floor.
Now, loosen the three 15mm bolts holding the entire dash assembly to the truck, near the right door. One of the bolts is hidden and can be reached with long extensions. Make sure the dash moves and you didn't miss any bolts.
With a friend's help, remove the 3 bolts and carefully lift the dash up and out enough to slide the AC/heater assembly out of the truck.
Be careful not to break anything, because the dash assembly is still connected on the driver's side. Also, watch out for coolant from the heater core.
Now open that bad boy up with a 4.5 or 5mm socket (I forgot which) and replace whatever is broken.
Do it all over again to put it back together "
