Here is how Tesla describes Range mode in their support page:
What is Range Mode?
In Model S and Model X, Range Mode conserves energy by limiting the power of the climate control system. When this mode is on, less energy is used when heating or cooling the cabin. When turned on in an All-Wheel Drive car, torque distribution between the motors is optimized to maximize range. You can turn on this setting through Controls > Driving > Range Mode.
In Model S and Model X, Range Mode conserves energy by limiting the power of the climate control system. When this mode is on, less energy is used when heating or cooling the cabin. When turned on in an All-Wheel Drive car, torque distribution between the motors is optimized to maximize range. You can turn on this setting through Controls > Driving > Range Mode.
