There is no fuse it's part of the Totally Integrated Power Module (TIPM), C11 connector, cavity 9 (X-21) http://www.jeepforum.com/forum/f98/t...module-458804/
It boils down to a bad connector, bad wire, bad ground at the horn, bad horn or bad TIPM.
First check to see if the horn has a good ground at the case.
Next apply direct voltage to the horn with a test lead.
Check wiring and connectors for damage.
If you can check the codes they are:
B2336–HORN CONTROL CIRCUIT LOW - (X21) HORN CONTROL OUTPUT CIRCUIT SHORTED TO GROUND or TIPM.
B2337–HORN CONTROL CIRCUIT HIGH - (X21) HORN CONTROL OUTPUT CIRCUIT SHORTED TO BATTERY VOLTAGE, EXCESSIVE RESISTANCE IN THE HORN OR CASE GROUND, TIPM
B2338–HORN CONTROL CIRCUIT OPEN - TERMINAL DAMAGE OR CORROSION, (X21) HORN CONTROL OUTPUT CIRCUIT OPEN, HORN CASE GROUND, HORN, TIPM.
B2371–HORN CONTROL CIRCUIT OVERCURRENT - TERMINAL DAMAGE OR CORROSION, (X21) HORN CONTROL OUTPUT CIRCUIT HIGH RESISTANCE, HORN CASE GROUND, TIPM.