Replace that horn while you can still hear it whimpering.

Dear Car Talk | Jan 01, 1995
Dear Tom and Ray:
Rhonda
RAY: Your car could just have low self esteem, Rhonda. But it's more likely to be a bad horn or a bad connection to the horn.
TOM: When you "blow" the horn, you send current to an electro-magnet. And that magnet make the horn diaphragm vibrate, and that's what makes noise.
RAY: So for some reason, the diaphragm inside your horn isn't vibrating enough. And it could be something as simple as a loose connection. If not enough voltage is getting to the horn, the diaphragm would vibrate weakly. So have your mechanic check all of the electrical connections to the horn first.
TOM: If they all turn out to be tight, then the horn itself is probably shot. In which case, you should go to your local auto parts store and buy a new horn. It only costs about 10 bucks.
RAY: But don't wait til it dies to replace it. Because if the horn won't make any noise, you'll never be able to find it under the hood!
Rhonda
RAY: Your car could just have low self esteem, Rhonda. But it's more likely to be a bad horn or a bad connection to the horn.
TOM: When you "blow" the horn, you send current to an electro-magnet. And that magnet make the horn diaphragm vibrate, and that's what makes noise.
RAY: So for some reason, the diaphragm inside your horn isn't vibrating enough. And it could be something as simple as a loose connection. If not enough voltage is getting to the horn, the diaphragm would vibrate weakly. So have your mechanic check all of the electrical connections to the horn first.
TOM: If they all turn out to be tight, then the horn itself is probably shot. In which case, you should go to your local auto parts store and buy a new horn. It only costs about 10 bucks.
RAY: But don't wait til it dies to replace it. Because if the horn won't make any noise, you'll never be able to find it under the hood!
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