Remove the rear door panel of a Mazdaspeed 3. This may be necessary to access the speakers, repair a window regulator, or access the sheet metal of the outer door panel. A 2007 model year was used for this project and the left rear door panel is shown.
Phillips #2 screwdriver.
Phillips #3 screwdriver (optional)
Mini-screwdriver (to release an internal electrical connector and to pry screw covers)
Electricians pliers or needle nose pliers (to pry up failed snap plugs)
Step 1: Remove screws
Pry up the screw cover under the door release using the mini screwdriver. It has a hinge on the end at car rear so pry it from the end at car front. Remove the small #2 screw under that screw cover. Slide the door release housing to the front and jiggle it free.
Pry up the screw cover under the door handle. It has a hinge at the top end so pry it from the bottom end. Remove the large #3 screw under that screw cover.
Step 2: Pry the panel loose
Tools are not needed for this step and will only serve to mark the paint on the inside of the door (may be visible). First pull off the little triangle piece that is snapped onto the door above the rear end of the panel. Use your fingers, It just pulls straight off of some nylon plugs. Set it aside and move onto the main panel. Use your fingers to pull on the edges of the panel. Start at bottom front and pull straight out to disengage the nylon plugs. Page down to see a picture of the back side of the panel. Note that the top edge of the panel has a lip that engages the door sheet metal to form the seal at the window. That edge cannot be pried. When the rest of the panel is free it will hinge on that top lip as shown in the photo. Each nylon plug is disengaged by pulling straight out on the edge of the panel.
Step 3: Remove the panel
Have the mini screwdriver handy (in a pocket or nearby) for this step. From the last step the panel is dangling from the top lip. Slide the panel up off the lip. Now the window switch wiring harness will hold you back. From the bottom, slide the mini screwdriver about 1 inch into the release groove that is on the back side of the white connector close to the panel. If you push it in far enough and pry a bit the connector will be free. You have to pull it down to remove it. The screwdriver will come with it. See the photos.
Now the panel is free and you can do whatever you need to with the panel or door.
Step 4: Fix the retaining plugs
Usually one or two of the white nylon retaining plugs come off the door panel where they belong. They need to be reinstalled or the panel may vibrate after re-installation. I used needle nose pliers and the mini screwdriver to work them free of the door sheet metal. They can take quite a bit of abuse and still serve as retainers when the panel is reinstalled. Note that replacements are readily available at parts stores, usually on a special rack on the floor (not behind the counter).
Step 5: Re-installation
Re-installation is the exact reverse except a screwdriver is not needed to push the electrical connector back on.