1. Remove the rear door unit.
2. Remove the screws, then remove the rear door latch and lock actuator.

3. Install in the reverse order of removal.
Front door latch and lock actuator removal/installation
Front door key cylinder removal/installationMazda 6 Service Manual: Distance Recognition Support System (DRSS) (Some models)
The Distance Recognition Support System (DRSS) measures the distance between
your vehicle and a vehicle ahead using a radar sensor (front) while the vehicle
speed is about 30 km/h (19 mph) or faster, and if your vehicle approaches a vehicle
ahead more closely than what is appropriate for maint ...
Mazda 6 Service Manual: Intake-air system removal/installation
Warning
When the engine and intake-air system are hot, they can badly
burn. Turn off the engine and wait until they are cool before removing the
intake-air system.
Fuel vapor is hazardous. It can easily ignite, causing serious
injury and damage. Always keep sparks and flames away from ...