Only the low horn works, not the high

the water and mud is getting in side of it and blocks the small holes up try turnung the horns around may have to relocate them

Assuming you have high and low horns, the low could have stopped working, or the one horn you have could be about to fail.
The horn uses a magnet to vibrate a plate to make the noise.
You could try a new replacement.

the mount is the ground for the horn circuit,, and they run in series,, so it doesn't matter which horn is first , to check the horn,, hook up jumper cables and ground the metal of the horn to Negitive post , and tap the horn clip, to the positive to see if it works

The click you here is the horn relay, You need to find the horns and check for power at the wire connectors. But you probably have a bad low and now a bad high not horn. since the relay clicks your fuse is good so that eliminates the fuse.

Are you check in the Power Distribution Box? this is located in the engine compartment.
The power distribution box contains high-current fuses that protect your vehicle's main electrical systems from overloads. Check the position 7, 20AMP (mini-fuse).

Get under the front bumper look strait up on the side of the battery there you will see two horns low/high. test voltage from battery at horn.

Keep us updated.

in the fuse box under hood is a horn relay #7 relay ,not #7 mini fuse

YOU HAVE TO HORNS HIGH AND LOW ONES... HIGH ONE IS SHORTED OUT.. LOW ONE STILL WORKS.. A NEW HORN IS ABOUT 45 DOLLLARS

check fuses
if they check out ok
find the horn sometimes they hide them pretty good once u find the horn unplug wires from it and take a jumper wire and hook battery directly to battery if horn doesnt work u have bad horn
if horn works u have a bad wire or bad horn button

horns stuck up ,behind the front bumper ,get assistant to hold on horn button and tap horns with a light hammer and see what happens

You need a new horn.