Speed-Reduction Setting

Switch "ON" the "CRUISE" (MAIN) switch.
Set to the desired speed, above approximately 40 km/h (25 mph).
Push the auto-cruise control switch in the direction of the arrow.

Fig 1: Pushing Auto-Cruise Control Switch - Speed-Reduction Setting
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Check to be sure that deceleration continues while the switch is pressed, and that the speed at the time it was released becomes the constant driving speed.
NOTE: When the vehicle speed reaches the low limit [approximately 40 km/h (25 mph)] during deceleration, the auto-cruise control will be cancelled.