5 Door

WARNING: This page is about a different car, the 2004 Mazda 3. However, it is still accessible from the selected car via links, so may be relevant.

Disconnect the negative battery cable.
Remove the service hole cover.
Disconnect the rear combination light bulb connector.
Remove the socket.
Remove the rear combination light bulb.
Install in the reverse order of removal.

Fig 1: Removing/Installing Rear Combination Light Bulb
Courtesy of MAZDA MOTORS CORP.