on my 2010 gen 3, there is a red flashing light on the dash after I lock the car. I looks like a door with a 'lock' flashing on it. I can lock the car, but the lock does not go off.
Generally in most Toyota vehicles the "Security" LED or immobiliser symbol will remain lit for the first 30 seconds or so when you lock the car, then it will flash every (approx.) 2 seconds, to warn dropkick would-be thieves that your vehicle is fitted with some sort of security device.
As pointed out above, it's the immobilizer light showing that it is active, or in other words, an anti-theft warning light. You should be congratulated on noticing it so soon. Many new owners don't notice it for the first six months or a year, and then come on PriusChat and post something like "NEW WARNING LIGHT ON DASH! WHAT DO I DO?" It takes a lot of typing to convince them that it has been there all along, while they were looking elsewhere. Tom
The immobiliser indicator light comes on when the car is turned off. It shows that the car cannot be started without a registered key in the car. Most Toyotas now have immobiliser systems and those with standard keys will shut off the light simply by inserting the key into the ignition. Gen II Prius turns off the light by putting the key fob into the dash slot.
Thanks. I would think that the warning light would flash once the doors are locked. But I guess that it would also make sense that the light flashes without the doors being locked for those instances when they are accidentally left unlocked when leaving the car...