Is this car lonely?
January 8, 2007 4:54 PM   Subscribe

So I have this car. It's not my car; I'm just keeping it for a friend. In my driveway. Empty. It's been here for about five months. Today, it started honking its horn at me. Not continuously. Just once in a while. Is the car lonely? Or is there some more rational explanation?

Hypotheses already tested:

The button isn't stuck. I've tried going out there and honking it once or twice, and it works normally.

I've tried leaving the engine idling for a while, on the theory that something is frozen or stuck and that that will solve it. It's still impatiently tootling at me.

There isn't an animal in there. Unless it's a very small and not at all easily startled animal.

It's just below freezing out there now, though not for the first time this winter, so I'm not sure if that's relevant. (It was much warmer -- near 60 degrees -- a few days ago. Again, not sure if that's relevant.)

How do I make it stop before the neighbors kill me? (With the caveat that my knowledge of car engines begins and ends with "it's that scary thing under the hood".)
posted by ook to Travel & Transportation (23 answers total) 9 users marked this as a favorite
I suppose you can just disconnect the battery and that ought to stop it, but man, I'm curious as hell just what the hell is causing that.
posted by jclovebrew at 4:56 PM on January 8, 2007

is it a Nissan?

A lot of Nissans (and some other cars), use the horn as an alarm. (although it usually honks continuously for a while, then stops)

This malfunctioned on my old Nissan and at one point started honking while I was driving, making everyone on the road think i was insanely honking at them! Theoretically, inserting the key in the door deactivated it, but this didn't always work. I think I ended up just pulling out the appropriate fuse.
posted by drjimmy11 at 5:00 PM on January 8, 2007

Best answer: to clarify:

using the horn as an alarm means the car has a way to activate the horn besides someone or something pressing the button on the wheel.

So even if you aren't doing things that would trigger the alarm, the care has an alternate way to activate the horn, and this could be malfunctioning.
posted by drjimmy11 at 5:02 PM on January 8, 2007

Response by poster: It is, in fact, a nissan.

It doesn't sound like an alarm -- the honking isn't in any sort of regular pattern except perhaps that of comedic effect. (Honk like crazy while I'm inside. Stop when I get outside. Tootle once just after I turn around to go back in. Etc.)

I just braved the mysteries of the fusebox (good idea! :) and have shut off the noise for now... but on the theory that I might someday want to put the fuse back in, anyone have any idea why it decided to start honking at me today?
posted by ook at 5:06 PM on January 8, 2007 [1 favorite]

Response by poster: Oh, should've previewed... yes, that does make sense, drjimmy...
posted by ook at 5:08 PM on January 8, 2007

Sounds like an intermittent short, possibly caused by moisture?
posted by ikkyu2 at 5:09 PM on January 8, 2007

It'll be the battery. The alarm is doing the same thing your smoke alarm does. Go give the car a decent long drive to charge it up again.
posted by bonaldi at 5:15 PM on January 8, 2007

Best answer: Yes, it is moisture freezing, either in the wiring harness or in one of the alarm sensors...... aside from removing the fuse, usually if you let the car warm up to normal operating temp and then turn the heat up inside of the car for awhile, the problem should go away.... I have seen this before, especially with Nissans......

You should be taking taking the car for a 15-20 minute ride every week anyways, it's not the best thing to leave a car sit outside in freezing temperatures for weeks or more at a time unless they have been prepared to do so......
posted by peewinkle at 5:20 PM on January 8, 2007

I had a 1992 Pontiac Grand Am that would do this when the temperature dropped to just about freezing. I would forget about it during the spring and summer, but when it started getting cold at night the horn would sound. Usually it occurred in the middle of the night, which meant that campus security called my dorm a few times at 2 am to tell me to turn my horn off. I wedged a few pennies in the steering column to take the pressure off the horn, and ended up taking the fuse out to kill the horn. Then I gave the car to my nephew and now he worries about it.
posted by cj at 5:20 PM on January 8, 2007

You should be taking taking the car for a 15-20 minute ride every week [...]

So. Yes, it is lonely.
posted by YoBananaBoy at 5:30 PM on January 8, 2007 [1 favorite]

Response by poster: peewinkle: I have been running the engine every now and then, but probably not often enough. I'll drive it around a bit tomorrow and see if that sorts out the moisture problem and/or makes it feel more like part of the family.
posted by ook at 5:36 PM on January 8, 2007

For charging the battery, driving around town may or may not be enough - if it's not too inconvenient, a 20 minute highway drive wouldn't be a bad idea. (Apologies if this seems obvious, but it wasn't to me, and I wish I'd known earlier.)
posted by spaceman_spiff at 6:28 PM on January 8, 2007

Response by poster: (FWIW the battery is already fully charged, has been all along; I've been idling it often enough to keep it alive.)
posted by ook at 7:03 PM on January 8, 2007

the battery might not be fully charged as you think... most alternators don't produce enough current at engine idle to actually charge the battery. as spaceman_spiff says, you have to drive the thing at highway speeds a bit.
posted by joeblough at 7:11 PM on January 8, 2007

i forgot to mention above that my mercedes will do the same thing with the horn when the battery gets low.
posted by joeblough at 7:12 PM on January 8, 2007

I had a friend with this problem. the plastic in the wheel was apparently shrinking around the contact thingers in the wheel, and pressing them down.
posted by Glitter Ninja at 7:23 PM on January 8, 2007

You should take it for a real, long ride. Brake pads oxidate. Oil dries away from the engine and accumulates in the pan. Batteries discharge. Gasoline is not as stable as you think, and degenerates with time.

So, yeah, the car is not only lonely, but right now it must be depressed and with suicidal thoughts.
posted by qvantamon at 7:33 PM on January 8, 2007 [1 favorite]

It's the nissan cry for help.
posted by acorncup at 8:07 PM on January 8, 2007 [1 favorite]

It could be a computer glitch. My car's computer went wacky, and it caused the horn to go off at random, until it was diagnosed by the shop.
posted by croutonsupafreak at 8:36 PM on January 8, 2007

fyi, just "idling" a car, while it may seem like the right thing to do, is actually worse for it than driving it for a 15-20 minute drive to run an errand or whatnot....

Driving the car puts the engine "under load" somewhat, allowing the car to get hot enough to burn of any moisture that accumilates in the oil, as well getting the tires warmed up a bit..... the cold weather is hell on tires and oil when cars just sit in the cold.... by driving the car, it allows the tires to get warm/hot, as well as the engine oil and trans oil....

Sure, by letting the car idle, you are ensuring the battery is charged, but it's actually worse on the motor oil because it is not getting hot enough to "cook off" the moisture.... not to mention the tires don't move.....

Don't be afraid to take the car out for a quick spin to the store as needed....... plus it will ensure that any moisture building up in the fuel tank is getting adequately mixed in evenly so that it may be burned off..... not enough in the gas to worry about as long as it doesn't form a pocket and freeze or build up too much.....

Just blast the heat for your drive once the engine is up to operating temp..... and drive for at least 10 minutes once the car is hot........
posted by peewinkle at 8:53 PM on January 8, 2007

Because of a wonky horn like this (but much worse), I had to replace the airbag in my olds. Does messing wiht the horn pad aggravate/relieve the problem at all?
posted by IronLizard at 8:54 PM on January 8, 2007

ook, I have no suggestions or advice, but I wanted to thank you for providing me with my first chortle of the day (your post) and first giggle of the day (your tags). Please give the Nissan a big hug for me and tell it I hope it feels better soon!
posted by scratch at 6:35 AM on January 9, 2007

Just disconnect the horn, it'll be one or two wires and they'll come off easy. Put a bit of tape over the end(s) so they don't short.

As far as the running and warming, while peewinkle is sorta right you can accomplish your goals just by starting and idling. The engine will warm up faster and better if you actually drive it somewhere rather than let it sit, however the real damage people do is revving an engine or driving hard when the car is cold. The difference between idling it to warm and driving it lightly to warm is much smaller than the difference between driving it lightly and revving the engine.

When you run/drive it to recharge the battery you should try to do so during the day; running the lights decreases the amount of juice the alternator can push into the battery, making it take longer to replace what you used up cranking the engine and reducing your efficiency.
posted by phearlez at 9:44 AM on January 9, 2007

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