This brake light switch, also referred to as the stop light switch is mounted to the brake pedal assembly. If it is faulty it can cause the brake lights to malfunction. BMW produced 2 versions of this part - 4 pin & 2 pin. Please check your car to ensure that you are ordering the correct part. This is the 4 pin swtich.

This item fits the following BMWs:
1992-1998 E36 BMW 318i 318is 318ti 318ic 323is 323ic 325i 325is 325ic 328i 328is 328ic M3
1989-1995 E34 BMW 525i 530i 535i 540i M5
1988-1994 E32 BMW 735i 735il 750il
1990-1992 E31 BMW 850i 850ci