Every car I've ever owned, that I can remember, had automatic dinger/chimes if the door was opened with headlights on. I'm very surprised, with all the other bells and whistles on this car, that there is no dinger for lights on reminder. I don't see this addressed anywhere.
I've had this chime only on cars lacking auto-off lights. Both my Prii, like both my Subarus (1997 to present), have / had auto-off lights, so don't / didn't need this chime. Your 2010-II is the same year and trim as my first Prius. It has auto-off, customizable for 0-30-60-90 seconds. (FWIW, I didn't own or drive a car with the reminder chime until 1986.)
i do have a large magellan gps hooked up to my 2015 prius because i like it better than the built in. anyway, it does remind me every morning to turn on my lights
I've got the auto-off headlights, but don't like them, prefer manually turning them on/off. For example, I often like to run with the headlights on in overcast daylight hours. So SOL I guess.
"Bells and whisles" are the higher trim models. Higher trims have programmable headlights to turn off automatically, or after 30, 60, 90 seconds. As Raytheeagle would say, club up to higher trim.
But if you forget to turn them off, the auto-off serves as a backup to prevent battery drain, so no harm done. Thus, no need for a reminder chime. In this case, 'higher trims' is really all trims.
Your Prius does one better: when you open the door, the lights turn off (or start the timer to turn them off). No need for a chime. Toyota vehicles have had this feature (sans the timer) since the 80s.
