Flashing red brake warning light

[Keith V.]

My 1973 1.7L has the instrument panel red brake warning light flashing, until I press hard on the brake foot pedal. I just checked the brake master cylinder and it is full. When I get home I will check the insides of each wheel for any leaks. The hand brake switch appears to be operating properly as the warning light came on after I drove a distance from home. But I will check that too. Brake foot pedal feels normal. Any ideas what else may be the problem? Thank you very much.

[djpateman]

It could be that the master cylinder switch needs to be reset via an external button. Or it could be impending failure of the MC. Also check the pedal cluster for a leak from the rear seal. Back in the 70's & 80's I was replacing MC's about every 7 years.

[Dave at Pelican Parts]

Could also be a short to ground in any of the brown/white wires in that circuit.

The light is triggered by one of the two brown/white wires getting grounded. That is supposed to happen when the handbrake isn't pressing down on the button under it (so the handle is raised), or when the switch in the master cylinder gets tripped by a pressure imbalance. But it will happen in any circumstance that provides a ground path on one of those wires. So if a switch is bad, or a wire is unplugged and lying on the chassis, or has chafed and is rubbing on the chassis...

--DD