1. Insert a screwdriver between the mirror and the base.

2. Push the base pin down to remove the rearview mirror.
Rearview mirror
Rearview mirror installationMazda 6 Service Manual: System wiring diagram
ABS (ABS/TCS)
DSC
FOREWORD
Before performing the steps in Symptom Troubleshooting, perform the
On-board Diagnostic Inspection. To check the DTC, follow the DTC Inspection
steps.
...
Mazda 6 Service Manual: Outside Temperature Display (Without Multi-information Display)
When the ignition is switched ON, the outside temperature is displayed.
NOTE
Under the following conditions, the outside temperature display may differ
from the actual outside temperature depending on the surroundings and vehicle conditions:
Significantly cold or hot temperatures.
Sudden ...