Horn Problem

Anyone good with 2000 Tundra electrical stuff? I am swapping the party favor horn for an ancient (though 12v), all steel 'aoogah' style motor driven horn.

When I make connections with the new horn through the existing wiring harnesses from the horns original to the truck, it does not work. It also seems that there is some link between toyotas two original horns such that if one is not wired, neither will blow. Is my only option to pull the wires back to where they originate and tie the new horn wires in there?

Note: the oogah horn does work, reliably, and has for the past 25 years or so. If I just touch the cables to the battery terminals it sounds every time...

Thanks!

Are you connecting the pos and neg to the proper terminals?