The headlight washers operate only if the headlights are switched on and there is sufficient washer fluid in the reservoir.
The headlight wash feature operates automatically with the windshield wash.
The feature operates every fourth operation of the windshield washers. The feature operates if the headlights are switched on and approximately 10 minutes has elapsed since the last headlight wash.
Switching the headlights or the vehicle's ignition off and back on again resets the cycle. See LIGHTING CONTROL and SWITCHING OFF THE ENGINE.