How to Replace Horn in a 1998 Ford Taurus sho?

My Horn has gone out to a small quite screech and i want to replace the horn but i don't know where it is and/or if i need a specific type of horn to use as a replacement please help.

Auto Zone or Advanced will know the right replacement part.

However, the noise could be like it is because there's a short on the wiring to the horn and that makes it sound goofy. You can test it easily, yourself. Take a piece of wire, long enough to go from the horn to the battery and disconnect the wire that's on the horn now. Take the piece of wire and connect it to the horn. Now touch the other end to the positive (+) side of the battery. It should sound. If it squeaks, then it's the horn, if it blares normally, then it's in the cars wiring leading to the horn.
Let's hope it is the actual horn since chasing the short could be a pain.

The horn is in the left front of the cowl, American Patriot is right that you should test that the horn is bad. Run a jumper wire to see if the horn is bad, it could also be a relay

So I just tested the horn and that's what's faulty thanks for the help people.