Hill Assist is always on. I live in Seattle and on our wet roads, its a blessing.
Hill Launch Assist (HLA) This feature helps assist drivers when accelerating the vehicle from a stop while on a hill or slope. When the brake pedal is released and the accelerator pedal is pressed, HLA prevents the vehicle from rolling forward or backward. It operates on a downward slope when the shift lever is in the reverse (R) position and on an upward slope when the shift lever is in a position other than the reverse (R) position. The HLA system will hold the vehicle for a maximum of 2.0 seconds while the driver is changing from the brake pedal to the accelerator pedal.