Honda Pioneer SXS700M2P 2019 Owner's Manual page 183

Brakes
Brake Light Switch Adjustment
Refer to Safety Precautions on page 105.
Periodically check the operation of the brake light switch. It is
located under the air guide plate (page 120) in the front hood, just
above -- and slightly behind -- the brake fluid reservoir.
The brake light should turn on just before the brake works.
Adjustment is done by holding the switch body and turning the
adjusting nut. Turn the nut in direction (A) if the switch operates too
late, and in direction (B) if the switch operates too soon.
UNDER FRONT HOOD
LEFT SIDE
A
B
brake light switch
Servicing Your Honda 173