Brake warning indicator light 1967-72 D5TZ-10A840-A
The brake warning indicator light (mounts in left bottom corner of the dash) on 1967-72 ford F-series trucks. Don't really look for it to come on because that's not the way it functions.
It's purpose is to come on ONLY if you have gotten air in the brake line or some other hazardous problem that could make the brakes unsafe.