Nice writeup Dan. Just took apart the doors in my mother's 2005 Silverado using these instructions. The 03-07 Classic doors are almost exactly the same, aside from a few differences.
Step 2: Behind the lock slider, there is a 7mm screw that needs to removed.
Step 4: DO NOT try to remove the switch panel, YOU WILL BREAK IT! There is a screw beneath the front end of the panel that can only be removed with the door panel off. Fortunately, there is no screw behind it that needs to removed.
Step 5: Like said above, there is no screw behind the switch panel. Before continuing to step 6, you need to remove two addition screws and a plastic push-in fastener.
- Pry off the small plastic cap towards the rear side of the door to reveal a bolt. Remove it with a Torx-20 screwdriver.
- Pull out the small plastic fastener towards the front side of the door. You can use a panel tool to pry up the fastener, but I was able to get my fingers under the door panel and pull it out that way.
- Remove the 7mm screw on the bottom of the panel.
Last step: Now disconnect the wiring harnesses from the switch panel. If it makes it easier for you, you can remove the switch panel by removing the 7mm screw underneath the front end of the panel and then prying up the rear end of the panel.
To remove the wiring harness that comes out at a 90 degree angle, pull the small gray lever around it towards where the wiring comes out.
Pay attention to where the wiring harnesses came from, some can fit into the wrong connectors. If you forget, they are labeled beneath the switch panel.