I just bought mine a few weeks ago but have the headlights set to go off automatically like in my LX470 so I'm not sure if there is a warning buzzer or not.. hopefully someone else here can help you. What did you drive before the GX and how do you like the GX so far?
Carol
A 97 Ford Explorer. A great and dependable truck, but long in the tooth. The GX is far more lux than the Ford. Apples and orange, really. With 600 miles, so far so good.