Hi
On later models the brake light is dual function:
As others have said it is a low fluid warning light , but I do not think triggers until the master cylinder reservoir is pretty well empty , so don't rely on it!
Secondly it functions as a "handbrake on" switch, so there are contacts between the handbrake and the transmission tunnel . These contacts can become rather dirty due to oil and dirt build up , in which case they will trigger "false" alarms.
I had the same issue on my +8 , every time I indulged in heavy breaking the light would illuminate , which I eventually traced to these contacts.
However , they really are placed in a most inaccessible place , so unless you have access to a lift and can work under the car , the only other method of access is to remove the transmission tunnel. This is again not a hard job , just time consuming as you have to first remove the seats (in itself quite a job as the nuts under the car are likely to be seized AND damaged) and then the tunnel. While it is off and you have access, you can do quite a bit of other preventative maintenance (e.g.: pedal bracket, clutch mechanism, inspect gearbox mountings etc)
Andy
