Austin, today I had to use the horn on my car, and it sounds very very funny….down right silly sounding. I don’t really use the horn that often but today it sure sounded weak. I have a Nissan Maxima, and the horn sounded like something you would hear on a kids bicycle not a car. Is there something stuck? The horn works it just sounds funny. Why?
Ellen,
Hi Ellen,
I would bet your car, as do most cars has two horns on it. One high tone and one low tone horn. When the two of these horns operate at the same time, you get a “normal” sounding horn, but with only one of these two horns operating you will get a flat or weak sounding horn.
Open the hood and have someone operate the horn so you can locate them, usually they are up towards the front of the vehicle in front of the radiator or A/C condenser. 
Then feel each horn with your hands as the person inside the vehicle operates the horn, the horn that is not vibrating is the bad one. Remove it and buy a new one from the dealership and replace it yourself…it’s just a simple job of removing a few screws and replacing the horn.
You can do it. I would not install an aftermarket horn bought from a regular auto supply store; the tone will probably not match your original horn so it will never sound quite the same as before.
Blessings,
Austin Davis