Sorry if this has been asked. My AC seems to vibrate the passenger footwell, as well as the driver footwell and steering wheel (less so). The AC was set to "fresh air" (for kids, 3rd row seats), and when the fan goes to 10/11 (either manual or auto), there's a VERY noticeable vibration by the feet. If I switch the AC to recirc (and it drops the fan speed to 8/9), the vibration goes away. If I turn the AC off, the vibration goes away. It's also not completely repeatable, has happened 3-4x in 3 days. Is this normal or should I contact the SC?