A low level of electrolyte fluid will cause the battery to discharge quickly.

Inspect the electrolyte level at least once a week. If it is low, remove the caps and add enough distilled water to bring the level between the upper and lower level (illustration).
Do not overfill.
Examine the specific gravity of the electrolyte with a hydrometer, especially during cold weather. If it is low, recharge the battery.
Battery Maintenance
Battery RechargingMazda 6 Owners Manual: Emission Control System
This vehicle is equipped with an emission control system (the catalytic converter
is part of this system) that enables the vehicle to comply with existing exhaust
emissions requirements.
WARNING
Never park over or near anything flammable: Parking over or near
anything flammable, such as dry ...
Mazda 6 Owners Manual: Front and rear fog light switch inspection
Light switch LH side
1. Remove the light switch. (See LIGHT SWITCH REMOVAL/INSTALLATION.)
2. Inspect for continuity between the light switch terminals using an
ohmmeter.
If not as specified, replace the light switch.
Light switch RH side
1. Remove the light switch. (See LIGHT SWITCH ...