Horn questions

Hi everyone,

I bought a new siren that can be connected to your horn input in order to cycle the tones - the idea being that you don't have to take your hands off the steering wheel in order to operate the siren. The wiring is pretty basic, just a relay that will switch the input away from the horn speakers and to my siren amplifier when I activate the emergency lights.

Here are my questions:

1) Is the horn on the Tacoma positively or negatively switched?
2) I traced the wire back from the horn speakers - does the wire loom contain just one wire, or does it have two? I think the horns are grounded by the mounts, but I'm not sure.

Thanks for the help!

 

Bump?