See
Figure 1. Models with heated hand grips have a variable heat control dial located on the end of the left hand grip.
Rotate the control dial to align the desired setting with the arrow on the grip. The heat settings range from 1 (minimum) to 6 (peak). Rotate to the OFF icon to turn off heat.
To prevent battery drain, the heated hand grips will only function while the engine is running. The hand grips produce peak heat with the engine running at cruising speed.
The hand grips are thermostatically-controlled, providing a constant grip temperature regardless of changes in the outside temperature.
Figure 1. Heated Hand Grips