Sick horn could be one of three things.
I have a 2000 Chevrolet Astro Van. The emergency warning device (aka, the horn) will work only if the outside temperature is above 55 degrees Fahrenheit. Sometimes, if the temperature is near 55 degrees, and if I hold the horn button down for 1 to 3 minutes, the horn will work. I'm about to buy an add-on button and attach it to an aftermarket horn, maybe with the "Dukes of Hazzard'' theme. All kidding aside, it is a serious problem because I live in a cold part of the country. -- DAN
TOM: There's a horn pad on your steering wheel. When you press on it, you push together two metal contacts.
RAY: When those contacts touch, they don't make the horn blow. There's an intermediate step you don't know about.
TOM: The horn takes too much current to safely run through your steering wheel, so those contacts in the wheel trigger a horn relay, which is a heavy-duty switch under the dashboard or the hood.
RAY: The relay closes and allows power to flow through to the horn itself, which sits in front of the radiator.
TOM: Start by checking the horn itself first. The easiest way: When the horn's not working, have someone honk the horn while you tap on the casing with a screwdriver. If it makes any sound at all, even some sick-goose-like half-honking, the problem is in the horn. Or hook a test light to it. If the light goes on when someone honks the horn for you but the horn doesn't make any noise, then you know the horn is getting current and just isn't working.
RAY: If the horn is NOT getting current, then it's either the contacts in the steering wheel's horn pad, or it's the horn relay.
TOM: I'd bet on the relay first. Why? Because it's easier to replace a $20 relay than it is to take apart a steering wheel.
RAY: If a new horn relay doesn't fix it, then it's in the steering wheel, and you'll have to take it to a mechanic and shell out some money. Or go for that "add-on'' horn button.
Got a question about cars? Write to Click and Clack in care of this newspaper, or email them by visiting the Car Talk website at www.cartalk.com.