1. Measure the temperature around the cabin temperature sensor.
2. Measure the resistance between terminals of the cabin temperature sensor.

Cabin temperature sensor removal/installation
Evaporator temperature sensor removal/installationMazda 6 Service Manual: Symptom troubleshooting
Verify the symptoms, and perform troubleshooting according to the
appropriate number.
Vehicles with ABS/TCS
Vehicles with DSC
*1 : DSC system contains traction control function, DSC indicator light goes
on and off while DSC operates.
*2 : DSC indicator light goes on and off while D ...
Mazda 6 Service Manual: Smart Brake Support (SBS) (Some models)
The Smart Brake Support (SBS) system alerts the driver of a possible collision
using a display and warning sound if the radar sensor (front) and the Forward Sensing
Camera (FSC) determine that there is the possibility of a collision with a vehicle
ahead while the vehicle is being driven at abo ...