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: Thermostat
THERMOSTAT REMOVAL/INSTALLATION
1. Remove the plug hole plate.
2. Disconnect the negative battery cable.
3. Drain the engine coolant. (See COOLING SYSTEM SERVICE WARNINGS.)
4. Remove the drive belt. (See DRIVE BELT REPLACEMENT.)
5. Remove the washer tank.
6. Remove the P/S oil pump.
Note
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Mazda 6 Service Manual: Push-Starting
Do not push-start your Mazda.
WARNING
Never tow a vehicle to start it: Towing a vehicle to start it is
dangerous. The vehicle being towed could surge forward when its engine starts, causing
the two vehicles to collide. The occupants could be injured.
CAUTION
Do not push-start a vehicle that ...