Trigger Lights Off

private var soundPlayed : boolean = false;
var audio : AudioClip; // Note change of capitalization of var name
var volume: float = 10.45;
var light : Light // Note change of capitalization of var name

function OnTriggerEnter(col : Collider){
	//Play Sound if player enters trigger
	if (!soundPlayed && audio) {
		// but only if it has not played before
		AudioSource.PlayClipAtPoint(audio, transform.position, 10.4);
		soundPlayed = true;
		// sound will not play anymore
	}
    light.enabled = false;
}

You could also use:
	var lights : Light []; //    which will use an array

and then use:
	for (var light : Light in lights) {
		light.enabled = false;
	}