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Brake warning light switch 1985 Chevy truck

I have changed the master cylinder and bled the brakes but I need to find out how to set the brake light switch that is located on a crossmember under the radiator. The master cylinder went bad and all the fluid leaked from the rear reservior causing the brake warning light on the dash to come on. How do I reset the switch?

Try kicking the brake pedal sharply. Many times, the proportioning valve will get stuck, and giving the brake pedal a sharp kick will “un-stick” it. If you do this and the light goes out, expect to have to bleed the brakes again, and try not to push the brake pedal too far down while doing so, so as to not activate the proportioning valve again. If it happens again, kick that brake pedal again and try again until you get the brakes properly bled.

You need to recenter the combination valve, and it requires this tool. http://www.costplustools.com/Kent-Moore-J-39177-COMBINATION-VALVE-BLEEDING-TOOL_p_7215.html

Place the tool under the bleed pin on the combination valve to hold it in position. Open the bleeder screw at the right rear brake and have someone press the brake pedal quickly. Close the bleeder screw and let up on the brake pedal. Remove the tool from the combination valve. Press on the brake pedal hard and that should recenter the combination valve so the brake warning light turns off.

Tester

I guess I will see the bleed pin when I look at the combination valve? Does this pin need to be held up or pushed in during the process?