I have a related problem, but not identical. I can say 90% sure it's nor the brake, nor the clutch switch at fault.
What happens is that "Hill Control Unavailable" suddenly pops up on the dash, particularly in cold weather. However, this only happens under the following conditions:
- headlights (short beam) are on
- I press the brake pedal
If I turn off the lights, the Hill Control warning light on dash also goes away. Also when the Hill Control warning is up, if go into reverse, the reverse sensors are malfunctioning and there goes another warning - Parking Sensors Unavailable. However, they seem to be working fine in good weather. Also noticed the parking sensor light (the switch on the car roof near the mirror) sometimes stays on.
Local Alfa dealer said they couldn't reproduce the issue. Maybe time for a new dealer?