1. Inspect for resistance between the front door speaker terminals using an ohmmeter.


2. To verify that the front door speaker outputs sound, apply voltage to the front door speaker and release using a 1.5-V battery.
Front door speaker removal/installation
Rear door speaker removal/installationMazda 6 Service Manual: Cruise Control (Some models)
With cruise control, you can set and automatically maintain any speed of more
than about 25 km/h (16 mph).
WARNING
Do not use the cruise control under the following conditions: Using
the cruise control under the following conditions is dangerous and could result
in loss of vehicle control.
...
Mazda 6 Service Manual: Tire Inflation Pressure
WARNING
Always inflate the tires to the correct pressure: Overinflation or
underinflation of tires is dangerous. Adverse handling or unexpected tire failure
could result in a serious accident.
Use only a Mazda-genuine tire valve cap: Use of a non-genuine part
is dangerous as the correct tire ...