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: Control Switches
Temperature control dial
This dial controls temperature. Turn it clockwise for hot and counterclockwise
for cold.
NOTE
When the mode is set to or
with the fan control dial in a
position other than 0 and the temperature control dial in the maximum cold position,
the air intake selector sw ...
Mazda 6 Service Manual: Direct Mode
Direct mode can be used for temporarily switching gears by operating the steering
shift switch while the vehicle is being driven with the selector lever in the D
range.
While in direct mode, the D and M indication illuminate and the gear position
in use is illuminated. Direct mode is canceled ...