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: Operating Tips for Audio System
WARNING
Always adjust the audio while the vehicle is stopped: Do not adjust
the audio control switches while driving the vehicle. Adjusting the audio while
driving the vehicle is dangerous as it could distract your attention from the vehicle
operation which could lead to a serious accident. E ...
Mazda 6 Service Manual: Engine control system operation inspection
Main Relay Operation Inspection
Verify that the main relay clicks when the ignition switch is turned to ON
position and off.
If there is no operation sound, inspect the following.
- Main relay (See RELAY INSPECTION.)
- Harness and connector between ignition switch and main relay termi ...