Reply to "Brake Warning Light"

Nope, not grounds and not the switch. It is varnish in the shuttle valve cylinder.

When you open bleeders during bleeding you create off-balance pressure in the system. Thus, you have one end still blocked, with full pressure, and one end open. This is the pressure differential the shuttle valve was meant to detect. But after years of no movement, varnish will build up the the cylinder for the shuttle valve, it moves, and it is stuck in place by the varnish.

Hit the brake pedal HARD several times. No need to be moving. Just turn on the key so the light is on, and go for it. Hopefully, the valve will move back to center and allow the plunger on the switch to extend, and open the light's circuit.

If that doesn't work, hit it again HARDER.

If all this fails, the next course it to remove the shuttle, clean, and put it back.

Do a find search for 'shuttle' and you'll find many posts on this.

The switch in question here is the one on the right. The other switch is the brake light switch.

Larry

NOTE: If the light is still on, then the shuttle valve has moved to one side, and the flow of fluid to that side (end of car) is somewhat restricted. This can affect your braking efficiency.