Name that wire

[Called3rdstrike]

I inherited a 1971 Duster with a 318 2bc and the only changes I know my father in law did was change to and electronic ignition system from points. Found this random wire without a home. Anyone know what it is or where it goes. Was hanging by the starter. Engine starts and runs. Has a push on style connector and is black in color in the same wire harness group as the ones running to the starter relay. Just can figure out where it goes.

 

[CRUZE 418]

Wire to the switch on the brake distribution block

 

[HemiSSDart]

Yes, you should have a the brake light on. Plug it into the distribution block where all the steel hydraulic lines go to below...

 

[Called3rdstrike]

Thank you all