Brake warning lamp possessed

[471_Magnum]

Okay... I just figured out why my brake warning lamp and parking brake switch have been removed from my car.

Just took it for a test drive. Under moderate acceleration, the warning light is illuminating. 

Wassup with dat!?!

Parking brake switch is still missing. I've got the lead taped-up, so it's not grounding out. That leaves the switch at the proportioning block.

Why would it light up under acceleration?

[Plumcrazy]

Unplug the wire from that switch, if that keeps the light out then my guess is the shuttle valve inside isn't in the center position.  
It's supposed to center itself but when they get old you have to help them sometimes by opening a front or rear bleeder screw while slowly pressing on the brake pedal to move it. You will have experiment to see which way it needs to go.

If the light still comes on you need to start tracing wires, it may be rubbed through somewhere.

[471_Magnum]

Disconnecting the switch is my next planned move.

I suspect the shuttle valve is shifting backwards under acceleration.

[Chryco Psycho]

the shuttle valve should not move that easily