So can anybody tell me why the light doesn't come on during braking?

I'm having this same problem, but my brake fluid really doesn't look that low. It's right in the middle between min and max. That was the first thing I checked. Time to check the pads I guess.

Does anybody have info on the pad thickness handy? Just wondering how thick new pads are, and how thin Toyota recommends letting them go before replacing them?

 

It doesn't turn on during braking because it doesn't slosh around as much. Like the sensor can't read the fluid level when accelerating.