It also controls the horn honking volume when you press the Lock button on the key fob (or key itself on the newer keys). Turning the volume all the way off was the first thing I did when I picked up my car.
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Incorrect! This little knob only controls the volume of the beep and has absolutely no effect on the volume of the horns. In fact, Lexus's don't use the horns at all to indicate locking or unlocking. B)
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OK, I stand corrected. I thought the sound was coming from the horns. I personally find the noise emitted from a vehice when someone locks their doors annoying, (listen, I just locked my doors!) so I turned the volume all the way off and just glance at the head or tail lights to make sure the car executed the door lock command. I'm glad Lexus gave us this option, some manufacturers don't.