2003 cavalier - horn not working

Hey all. On my wife's Cavalier when you press the horn you get no noise. However, when you lock the doors you get the beep from that. Anyone know what could be wrong and how easy is it to fix? Is it worth me trying to fix myself or should I just take it in?

Thanks!

Still running the stock steering wheel i suppose? Also has it ever been wrecked.

Yep, still the stock steering wheel and it was backed into once with cosmetic damage, which was repaired.

Just amking sure the airbag never blew.

Check the fuse? My horn now goes crazy every now and then for no reason so I just took the fuse out. Mabye a previous owner did that?

Thanks for the suggestion, the fuse didn't blow. She bought the car new, so there was no previous owner. Guess I gotta take it in.