Brake master cyl sensor

[Rads]

Hi Guys,
i am having a bit of a prob, can you get the float sensor for the master cylinder separate or does it only come complete with resovoir etc, i have checked the levels etc and all is ok with the system. the brake light on the dash is on but not as bright as when the handbrake is on.
is the sensor the same as any other toyota's

[Dobbslc]

I found that the fluid level has to be very high to extinguish the light on my 3rd gen. Just above the max line.