Classic/Antique Car Repair: Brake light

Question
I have a 1972 c10 pick up 350 my brake light. Stays on all the time my brakes are good and no leaks

Answer
There are two ways that causes the light to come on. The first is the emergency brake applied and the second is the switch in the pressure differential valve is sensing that the hydraulic pressure in the two system is unequal or that the valve was not centered if the brakes were bled.The first thing that I would do is to lift the e-brake pedal with my toe while holding out the e brake release handle and watch the light. If it goes off then the e brake cables are binding or out of adjustment. If it does not go out disconnect the wire to the switch which is located on the pedal under the dash. If the light goes out replace the switch. If it does not go out then you will have to center the pressure differential switch by installing a special tool to center the valve and bleeding the brakes.