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Cold-hating horn in van easy to test

DEAR TOM AND RAY: I have a 2000 Chevrolet Astro Van. The horn will work only if the outside temperature is above 55° F. Sometimes, if the temperature is near 55° F , and if I hold the horn button down for a minute or two, the horn works. Once I get the horn to blow, it will work all day. I’m about to buy an add-on button and attach it to an aftermarket horn, maybe with the “Dukes of Hazzard” theme. Seriously, I live in a cold part of the country, and for many months, the days above 55 are few and far between. Please help! – Dan

RAY: This is the easiest question we’ve had all day. As modern cars go, the horn system is a very simple one.

TOM: Even for my brother! 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. “Why not?” you say. “That’s what happens in my car!” Well, yes, but 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 just a heavy-duty switch that lives either under the dashboard or under the hood.

RAY: Then the relay closes and allows power to flow through to the horn itself, which sits in front of the radiator.

TOM: So, one of those three components is not working. Start by checking the horn itself first. The easiest way to test it is – when the horn’s not working – have someone try to honk the horn while you tap on the casing with a screwdriver or something. If you can get it to make any sound at all that means your problem is in the horn..

TOM: You also can test the horn by hooking up a test light to it. If the test 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 you know it’s in the steering wheel, and you’ll have to take it to a mechanic and shell out some money, Dan. Or go for that “add-on” horn button. Good luck.

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