1982 Parking Brake Question

[hartishart]

I bought this 82 Sierra 3500 with the parking brake assembly not working, it wouldn't stay engaged. With a ton of oiling, it now stays engaged, but I don't have a brake light coming on when it is engaged. There is a brown wire that looks like it is supposed to trip the light on when it is engaged, but I don't see anything to attach it to, there's no switch or anything like that, just the parking brake assembly. Is there supposed to be a switch on the assembly? Any help would be greatly appreciated!