Ford Mercury Villager 1997 Owner's Manual page 96

Speed Control (If equipped)
The speed control system allows your vehicle to maintain a set
speed above 30 mph (48 km/h) without keeping your foot on the
accelerator pedal.
Avoid using the speed control when driving under the following
conditions:
it is not possible to keep the vehicle at a set speed
in heavy traffic or in traffic that varies in speed
on winding or hilly roads
on slippery roads (rain, snow, ice, etc.)
in very windy areas
To activate the speed control, push the main switch (CRUISE
CONT. ON); the switch is located in the group of controls to the
left of the steering wheel. The indicator light on the switch
will come on.
Speed control main switch location
92