Stoplight Switch
WARNING: This page is about a different car, the 1990 Oldsmobile Toronado, 1989 Oldsmobile Toronado, and 1988 Oldsmobile Toronado. However, it is still accessible from the selected car via links, so may be relevant.
Brake light switch input is provided to EBCM pin 12 when brake pedal is being depressed. This alerts EBCM to increase sensitivity to wheel sensor input signals. This input consists of a 12-volt signal on circuit No. 20 of the normally open brake light switch.