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: Close Proximity Warning
If your vehicle rapidly closes in on the vehicle ahead because the vehicle applies
the brakes suddenly while you are traveling in headway control, the warning sound
activates and the brake warning is indicated in the display. Always verify the safety
of the surrounding area and depress the bra ...
Mazda 6 Service Manual: Woofer inspection
1. Inspect for continuity between the audio amplifier connector terminals and
woofer connector terminals using an ohmmeter.
If not as specified, replace the related wiring harnesses.
2. Verify that there is battery positive voltage at the woofer connector
terminal A (4SD) or C (5HB) u ...