Here is a write up by a member of GM-Trucks.
I didn't want to type all this cause I know I have already done it here before, but I can't find it so I'll do it again. Engage emergency brake, turn key on, shift into lo, pull instrument cluster/radio bezel off. Remove the trim piece at both side panels (where the fuse box is on the driver side same on opposite side), remove both of the passenger hvac vents on both sides of the handle in the dash. Remove the A pillar moldings (that is the trim on either side of the windshield going from roof to dash) they just pull off but they might be tight. Inside the vents that you just removed there are release tabs on the sides of the pull handle, push in the tabs and pull off the handle. Remove the panel between the windshield and the dash pad (be careful with that ambient light sensor in the middle pull the panel up slightly and remove any connectors before yanking it out) Then all that is left are the screws, I don't remember how many off hand. There should be 2 on the sides under those covers (the fuse box cover and the same one on the right side), then there is like 4 or 5 more around the part where the instrument cluster bezel was and a few more on the passenger side inside the vent holes I think. Then pull it all out Don't worry it's not heavy at all it's a one person job not like the old dashes. It looks like alot but it's really not that bad, I have the whole deal down to about five minutes, if it takes much longer than a half hour to get it off there I'd be surprised.
Good luck to ya.
haven't done it yet, my recirc door is jammed up and need to get a new one installed.
Good luck and let me us know any part numbers you come across, sounds like I need to do the same thing