1. Measure the temperature around the water temperature sensor.
2. Measure the resistance between terminals of the water temperature sensor.

Water temperature sensor removal/installation
Refrigerant pressure switch removal/installationMazda 6 Service Manual: Scheduled maintenance
SCHEDULED MAINTENANCE TABLE
For Europe (L.H.D. U.K.)
Chart symbols:
I : Inspect and repair, clean, adjust, or replace if necessary.
(Oil-permeated air cleaner elements cannot be cleaned using the air-blow
method.)
R : Replace
T : Tighten
L : Lubricate
Remarks:
To ensure efficient oper ...
Mazda 6 Service Manual: Front passenger air bag deactivation indicator light
This indicator light turns on to remind you that the front passenger front and side air bags and seat belt pretensioner will not deploy during a collision.
If the front passenger occupant classification sensor is normal, the indicator light turns on when the ignition is switched ON. The ...