Not sure about 3rd wire to terminal

Hi I’m replacing faulty terminals and my battery on a 1989 chevy g20

and i noticed a 3rd wire that looks like it ought to be attached to one of my terminals, though i don’t recall pulling it off of the last battery. Which, if either, terminal should i attach it to? Thanks for any help

No idea. If nobody here knows, you could leave it disconnected (tape to prevent short circuit) & try driving the g20, and if some function doesn’t work , that wire is probably related. Suggest to not hook that wire up to anything at all until you know for certain. Your best bet is probably to ask this question at a Chevy Dealership shop. You local inde shop my know the answer as well. My guess, that wire isn’t supposed to be connected to either of the battery terminals. (It could be associated with some aftermarket gadget, like a car- alarm system.)

Those circuit brakers were added to the van, not factory. Follow the wires to see what they power, there are accessories that were added to the van after manufacture of the vehicle. Is this a custom van?