The rear view mirror's position can be adjusted to enable sufficient confirmation of the rear view.
Adjusting the height of rear view mirror
The height of the rear view mirror can be adjusted to suit your driving posture.
Adjust the height of the rear view mirror by moving it up and down.

Anti-glare function
Responding to the level of brightness of the headlights of vehicles behind, the reflected light is automatically reduced.
Changing automatic anti-glare function mode
On/off
When the automatic anti-glare function is in on mode, the indicator illuminates.
Vehicles without a smart key system: The function will be set to on mode each time the engine switch is turned to the "ON" position.
Vehicles with a smart key system: The function will be set to on mode each time the engine switch is turned to IGNITION ON mode.
Pressing the button turns the function to off mode. (The indicator also turns off.)

■To prevent sensor error To ensure that the sensors operate properly, do not touch or cover them.

Doing so may lead to mishandling of the vehicle and cause an accident, resulting in death or serious injury.
Steering wheel
Outside rear view mirrorsToyota CH-R Service Manual > How To Troubleshoot Ecu Controlled Systems: How To Proceed With Troubleshooting
HOW TO PROCEED WITH TROUBLESHOOTING
OPERATION FLOW
HINT:
Perform troubleshooting in accordance with the procedure below. The following
is an outline of basic troubleshooting procedure. Confirm the troubleshooting procedure
for the circuit you are working on before beginning troubleshooting.
...
Toyota CH-R Owners Manual > BSM (Blind Spot Monitor): RCTA function
The RCTA functions when your vehicle is in reverse. It can detect other vehicles
approaching from the right or left rear of the vehicle. It uses radar sensors to
alert the driver of the other vehicle's existence through flashing the outside rear
view mirror indicators and sounding a buzzer ...