Aha, I see, thanks for the clarification.
When assembled, the switch must be quite hidden above the pedal support, because I looked carefully, and didn't see it.
Anyway, just this diagram alone shows that what driver125 experienced must have been a coincidence.
It's self-evident that the brake light are driven by their specific switch, while the hybrid system (which obviously needs to sense the pedal position through its whole excursion) must be driven by the stroke sensor.

 

Sorry to jack this thread, but this comment sounds somewhat like the "issue" that I am having. I have a 2006 400h if that matters. When I hit the brakes I feel the regenerative braking happen and it always seems to "pull" the car to the left. I'm not sure if when the car starts to "pull" that it is the regen or the friction brakes doing this. But is this normal? I don't like feeling like I'm not in control of the car.

Second, (not sure at what speeds, but seems to happen moreso when I'm going faster or accelerating like you mentioned above) when I hit the brakes there is a very noticeable stutter when what feels like going from regen to friction where it seemingly losses braking friction or grabbing power. Not sure what this is, but it is only for a split second. But split seconds matter when you are driving and trying to stop.

 

@elfnumber1 - I'd go to mechanic - to check your brakes and wheels; does it pull to the side when you're not applying brakes?