Javascript google maps api, marker not rotating icon

Question

The marker just does not rotate, why?? I am using Google Maps Api V3 I am using a setInterval because my car is moving along the map And needs to face the direction of the route (for now bearing is just pre set).

var marker = new google.maps.Marker({
    icon: {   
        url: "../includes/images/car.png",
        scale: 1,
        rotation: 0  
    },
    map: map,
    position: overview_path[0],
    optimized: false
});



var counter = 1;
setInterval(function() {
    debugger;
    var bearing = counter * 15;
    marker.setPosition(overview_path[counter]);
    var icon = marker.getIcon();
    icon.rotation = bearing;
    marker.setIcon(icon);
    setTimeout(function(){
        map.panTo({
            lat: marker.getPosition().lat(),
            lng: marker.getPosition().lng()
        })
    }, 2000)
    counter++;
}, 1000