My horn still does not blow in my maxima 2006 after fuse replacement

Check Fuse 42 and also the horn fuse and relay.

https://fuse-box.info/nissan/nissan-altima-l31-2002-2006-fuses-and-relays

..

Check the fuses

Check the fuse

The horns are located in behind the headlights

its shorted, that line, the fuse blew saving you a nice fire.
are you using the correct fuel shown in you operators guide, see index , fuses.

do not mess under dash until you defeat those air bags, they can kill you. (break a neck easy) the schmatic is here.

official FSM
https://suzukipitstopplus.com/Products/1066-2006-forenza-reno-service-manual.aspx
$4 cost, dirt cheap.

first look at the actual horn, see damage there, it or the plug.
pull its plug and safe off (means tape it) and see if fuse blows yet?
always work the simple side first, not air bag side,or the
air bag clock spring, inside, steering last.

its either path A shorted, (most likely but fate wins)
or Path B, shorted relay coil.
if horn unplugged, fixes blowing fuse, the horn is bad.
easy huh?

start by checking your fuse. if its not blown, then make sure you have power going to the horn when horn is engaged. If you have power, then horn is blown, time for a new one.

check for the right fuse amperage. install the correct ampere fuse. thanks .

The horn may have a short. Try pulling the connector off the horn, put in a fresh fuse, then try to blow the horn. If the fuse blows, the short is in the wiring. If it doesn't blow, you need a new horn. Any more questions, please let us know.

horn may be shorted internally. Try pulling the connector off the horn, put in a fresh fuse, see if it blows.

If it still blows, you have a short in the wiring or the relay. If there is no obvious short in the wiring, change the relay.

If the fuse doesn't blow with the horn disconnected, replace the horn.

1st check fuse. Then see if power is coming to horn. A simple power checker can be found at most auto parts store. It may also have a horn relay. Look up your wiring at cargrus. If you still have problems contact me back.