Give your small car the horn it deserves

Dear Car Talk:

Why is it that car manufacturers have decided that the smaller the car, the wimpier the horn should be? My pickup has a nice, deep, loud horn. But my imported crossover almost sounds apologetic.

When you have to use your horn to warn someone that they're coming over into your lane, or censure someone for cutting you off, they're like, "Oh it's a little car, no big deal." – Mike

RAY: You're right, Mike. It should be the opposite, right? The smaller the car, the more intimidating a horn it needs. It's why little dogs have sharper teeth.

But you can swap out your horn, Mike. A bigger horn doesn’t take up much more space. And there’s no technological differences between big horns and small horns.

So, go to a junkyard and pull the horns off a 1976 Peterbilt tractor. Then, duct tape those babies to the vent window of your RAV-4 and watch people clear out of the way. People will laugh at you when they see the little car making all that noise, but they’ll get out of the way first.

Actually, that’s overkill. Funny, but overkill. What you can do is find another passenger vehicle with a horn you like.

Let’s say it’s your pickup truck.

Go to the dealer and ask the parts department to sell you the horns for that truck. There will be two of them. Horns have two notes, which is what creates that dissonant horn sound.

Then, have your mechanic pull the horns out of your little import and replace them with the bigger horns. He may need to fiddle around with them to mount them, or maybe even change the size of the wires, but it’s not rocket science. And they all run on 12 volts, so he should be able to make it work.

When it’s finished, sneak up to your least favorite neighbor and give him a friendly beep “hello.”

Is this dealer blowing smoke?

Dear Car Talk:

I have a 2007 Mercury Marquis. The A/C never can make up its mind as to where to direct the air flow. It comes out the dashboard vents, then changes its mind and sends the air out the defrost vent. Then to the floor.

There's no real pattern. I've spent $1,800 at the local Ford dealer and the problem never changes. They claim to have replaced stuff under the dash, but I've seen no evidence that they ever touched it. They have touched my money though. – Herman

RAY: Geez, I think these guys owe you a lot of money back, Herman.

The first thing I’d check would be the vacuum reservoir. The “blend doors” that direct the airflow under the dash are controlled by something called vacuum motors. And the vacuum needed to operate them is produced by the downward motion of the pistons inside the cylinders.

Every engine produces plenty of vacuum at idle and at low speed. But when the engine runs faster – when you begin to open the throttle – vacuum drops.

To make sure the blend doors don’t go crazy when the vacuum drops, lots of cars have something called a vacuum reservoir, which is a simple plastic container, about the size of a Nerf football, that stores vacuum. Its job is to provide vacuum to keep the blend doors from closing and opening haphazardly when you accelerate.

So, I hope they replaced that.

If that’s not it, it could be something as simple as a bad connector, hose or check valve. The easiest way to find the vacuum leak (which is what I think you have), is to use a smoke machine. As a bonus, you can also throw a helluva party in your 2007 Marquis while getting your diagnosis. Be sure to bring your Pink Floyd albums with you when you go the shop. We’ll introduce smoke into the system instead of vacuum. If there’s a leak, we’ll see it.

That’s what your dealer should do next. And if they find a faulty vacuum reservoir or a bad connector or check valve, I think they owe you $1,800 back, minus the cost of the $150 vacuum reservoir, the $5 tee connector or the $3 check valve.

Or you might want to just go to another mechanic. Search at for a recommended shop near you and start over with a smoke test. If they figure it out, then go back and ask for a full refund, Herman. Or go to small claims court if you need to. I think they’re going to owe you.

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