Blinking Brake Light - 73E

[Crachian]

My brake warning light blinks constantly, and I suspect it's a bad switch in the parking brake.

I unbolted the brake lever assy from the floor without detaching the parking brake cable, and then I ran out of time.

Where is the switch and how do I get to it? And is there any way to test it without dissassemblying it all? The model is a 1973 E.

Thanks,
Cabrach