Car horn won't shut off

So I get an overhead page at the hospital I work at today. I call the operator and she tells me my car alarm is going off in the parking lot. I go out to shut it off and find that it isn't the alarm but the horn is just blaring non-stop. The only thing I could do to shut it off was disconnect the battery. I switched the horn fuse, reconnected the battery but as soon as I hit the horn to test it, it went off but would not turn off. So I unhooked the battery again and removed the fuse. I reconnected the battery and am able to start the car so atleast now I can drive it to the mechanic without hte horn going off. Anyone know how to fix this?

Edit: it's a Mitsubishi Montero Sport XLS 2002 and yes, the horn is part of the alarm system.

Um, unplug it?
Then have this moved to general chit chat.

Well, it would be nice to know what kind of car it is. Some car horns are integrated into the alarm system, some are not.

I had this issue with my 2000 Audi A4 and it ended up being a dying glass breakage sensor. It would go off intermittently (that car uses the horn as the alarm).

It might just be the horn contacts in the steering wheel have gone bad. Hopefully they are not hooked through the airbag assembly - if so then you are in for a large repair bill.

either figure out what fuse it is and pull it, or locate the horn itself and disconnect it

maybe someone tried to prank you and messed up? We pranked my friend by wiring his horn to his break pedal, so whenever he hit the break his horn would blare

Germelli1 said:

maybe someone tried to prank you and messed up? We pranked my friend by wiring his horn to his break pedal, so whenever he hit the break his horn would blare

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That it awesome!

If this does involve replacing the airbag, I'll be going without a horn for the rest of this car's life. I'm not forking over $1000 for a new airbag just because it causes teh horn to malfunction.

horn relay fused closed?

my vote is for swapping out the relay.

If you do disconnect it, are you sure it will pass inspection? I know they test the horn here. It might need to be fixed eventually, at least working enough to pass the inspection.

Germelli1 said:

maybe someone tried to prank you and messed up? We pranked my friend by wiring his horn to his break pedal, so whenever he hit the break his horn would blare

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Hah! I hooked my BIL's to the starter.

jfulton said:

If you do disconnect it, are you sure it will pass inspection? I know they test the horn here. It might need to be fixed eventually, at least working enough to pass the inspection.

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Inspection? I live in New Mexico, I don't think we have anything like that. Hell people don't even use turn signals out here.

david_42 said:

Hah! I hooked my BIL's to the starter.

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ooo good idea!

Germelli1 said:

ooo good idea!

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I've done the left turn signal. The victim is usually "out in traffic" before it goes off.

chuckjaxfl said:

I've done the left turn signal. The victim is usually "out in traffic" before it goes off.

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Ya we did it on his break/only when car was running 12V (don't know the term for that). Since he had a stick shift he never pressed the break until he got to the end of the driveway.

It worked out for us but your plan sounds universally awesome!

long shot, but in jeeps (what i drive) there is a clock spring in the steering wheel assembly that can go bad. usually that results in the horn not working though. you can remove the airbag and put it back in without having to purchase a new one if you need to replace another mechanism behind it etc. good luck!

well, after work I go out to the car hook the battery back up....no horn, make sure the fuse is in....no horn, start the car...no horn, honk the horn..horn goes off but stops. Now I can't get the problem to repeat itself. I'm sure it will go off about 2am tonight.

That happened to a friends Jetta. We pulled the fuse to stop the horn, and the steering wheel (or the part that activates the horn) needed to be replaced.

That happened to a Jetta that I owned 4-5 years ago. turned out it was the radio not hooked up right from the factory. The car kept thinking someone was trying to steal the radio, setting off the alarm. New radio, no more horn.

i just want to say if this does have an air bag and if you have never been into a steering column do not attempt this yourself there is alot of potential energy contained in there and will hurt you if the proper precautions are not taken.

jppostKW said:

i just want to say if this does have an air bag and if you have never been into a steering column do not attempt this yourself there is alot of potential energy contained in there and will hurt you if the proper precautions are not taken.

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Very well said. If you are not familiar with removing airbags or working around air bags I would not recommend trying to remove the air bag.

Thanks, I definitely will not be attempting any of this on my own. I don't know anything about cars and am not about to start tearing my car apart. I'll let the mechanics deal with it....if it decides to do it again. So far it was a one time incident.

Did this scream "Little Miss Sunshine" to any one else. lol

steinsato said:

Thanks, I definitely will not be attempting any of this on my own.

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which is why it's in the DIY forum?

Boerderij_Kabouter: Did this scream "Little Miss Sunshine" to any one else. lol

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The door keeps falling off my VW van...

Horns usually work off of an open ground circuit. when you hit the button on the steering wheel it completes the group and off goes the horn. If something managed to ground your horn to the frame it could possibly do this.

Electrical gremlins are the worst thing to track down in a car.