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: Jam-safe Moonroof
If a person's hands, head or an object blocks the moonroof while it is closing,
the moonroof will stop and move in the reverse direction.
WARNING
Make sure nothing blocks the moonroof just before it reaches the fully closed
position: Blocking the moonroof just before it reaches the closed posi ...
Mazda 6 Service Manual: Air intake actuator inspection
1. Connect battery positive voltage to terminal D or F and ground to terminal
F or D of the air intake actuator.
2. Verify that the air intake actuator operates as shown below.
If not as specified, replace the air intake actuator.
...