Hello: fixya i've a problem with my 2008 acura tsx and the horn does not work or blow i've checked the fuse and relay and both or good so what should i do need help asap need to get car inspection !

Is the air bag light lit on the instrument cluster ? Inside the steering or under it actually ( steering wheel ) on top of the steering column is a part ,called a clock spring .Acura calls it a cable reel . Has wiring that connects the steering wheel electrics to the body electrical . These tend to break after so many times of turning the steering wheel left to right . Here's a video on how it works .
How Clockspring Works

If the air bag light isn't lit , maybe the horn relay went bad . heres a video on how to check the electrical circuits for horn .
VEHICLE RELAYS Operation Diagnosis

Fuse 28, a 10AMP fuse may be blown/bad. You may need a new one. Or your bulb may have burnt out. It's 12 years old. Any auto parts store guy could help you with it. (lower left side in this pic)
http://cimg0.ibsrv.net/cimg/www.acurazine.com/1024x768_85/240/fusediagram-164240.jpg

Video shows you how.
Blown Fuse Check 2004 2008 Acura TSX 2008 Acura TSX 2 4L 4 Cyl

tsx console vsa moonroof hazard button guide - YouTube

? 3:00
www.youtube.com/watch?v=b0M0VMWLIFk
Jan 8, 2009 - Uploaded by Jeffrey Liu tsx console vsa moonroof hazard button guide ... Like the RonJonLight :P ... GTA Car Kits - Acura TSX 2004-2008 install of iPhone, iPod and ...

have you had the coolant checked as if has low level some systems wont start up as can cause damage so get the refrigerant checked as a first step

horn relay located on the right side kick panel,you will see a row of relays,if horn relay is okay, more likely your horn control pad has a short inside causing horn button contacts to stick causing horn to keep blowing.

I would trace the wire from the horn and see if it was inadvertently damaged when the alternator was installed. If you have a voltmeter, you can remove the horn fuse and check to see if there is continuity between the horn (non hot side) of the fuse and the car body. This would indicate a short in the wire running from the fuse box to the horn. You can also look around the alternator mounting area to see if any wires are being pinched. Hope this helps. Good luck!

I would take it apart and try a new battery. Make sure there is no corrosion on the contacts where the battery sits. If that doesn't fix it time for a new remote. Unless you have a bunch of miles on it it may still be under warranty. See your Acura dealer.

I owned a 2005 TSX. They are great cars!

Bob

If you can locate and pull relay, do that, if not, pull wires off at horn if you can, otherwise pull fuse. If you have other relays same in area of horn relay (same number on relay) try one of them in that horn spot to see if maybe it's just a stuck relay.If you pull fuse for horn, you may find out something else on same fuse, so make sure you check everything else is working.

Try the relay for the a/c problem.  Try the relays for the headlights also.