Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
Is the ABS light on as well? If you disconnect electrical connector at master cylinder and at park brake pedal, will the light go out?
Sorry for the delay. Checked schematics and I'd like for you to follow the brake lines down from the master cylinder to the proportioning valve. There is a single wire attached to the proportioning valve, disconnect this wire and see if the brake warning lamp goes out.
This same wire also goes to the ignition switch. This is for bulb test, brake light should be on with key in Start position. Should be grounded only in Start position. Find an area of the wiring at the column that is easy to get to and cut the Tan/White wire. See if the light goes out. If it does then the fault is in the ignition switch.