How do you COMPLETELY disconnect a car's factory-installed panic alarm?
October 26, 2014 11:54 PM   Subscribe

I need to know how to completely disconnect a factory-installed panic alarm on a 2002 Hyundai Sonata to keep it from drawing power on the battery.

(This is LillyBird's husband posting because she didn't know how to phrase the question. Also, I apologize if I'm posting this in the wrong category, but it's the closest that fit.)

We have a 2002 Hyundai Sonata. According to our mechanic, there's a problem with the car's factory-installed panic alarm that's making it draw power from the battery, essentially draining the battery so the car won't start (almost like accidentally leaving the interior lights on).

I need to know how to completely disconnect the alarm from the battery so it stops drawing power and killing the car. I looked online and found some instructions for disconnecting a panic alarm from other vehicles, but I can't find anything for a 2002 Hyundai Sonata, and I don't want to just start pulling wires.

I tried removing the fuse that I think controls the alarm (I can't figure out exactly which fuse it is for sure), but it didn't work. If anyone knows which fuse this is for sure, I'd appreciate knowing that, too.

Any help is much appreciated. This car is on its last legs, and I'm completely unwilling to dump any real money into it other than basic upkeep/maintenance costs. I just need it to make it through the winter before I pony up and buy a new car.

Thank you in advance. (Just to note: I'm a fairly handy person and can follow instructions well, but when it comes to cars, I'm quite ignorant. I basically don't know anything about them, so please keep your responses as layman as possible. Thank you!)
posted by LillyBird to Home & Garden (12 answers total)
Can you give us some more information as to why you believe it is the alarm killing the battery and over what period of time the battery is dying? How long is the car sitting for before it goes flat?

It is a tiny, tiny draw from the alarm if it is operating correctly and the car should be fine for several weeks with a healthy battery, so I would be very surprised if this is the issue unless something else was wrong.

1: What is the age of the battery?

2: How long is the car left parked before it doesn't have enough charge to restart?

3: Is the car parked on the street or in the garage? If in a garage does it have power?

That may help us establish the root cause and suggest some cheap solutions.
posted by Brockles at 4:44 AM on October 27, 2014 [1 favorite]

Are you sure it is specifically the "panic" alarm that is draining the battery and not just the regular alarm system? Usually the "panic" alarm is a button on the keyfob that activates the regular alarm system. It might help to look for info on disabling the entire alarm system rather than the panic alarm specifically (are car alarms ever useful? I have never in my life heard one and assumed a car was being stolen, rather that it's someone who's set their own alarm off accidentally).
posted by EndsOfInvention at 5:03 AM on October 27, 2014

Is there a fuse for the alarm system? I think that would be the quickest way to cut it off from the power source.
posted by COD at 5:04 AM on October 27, 2014

Wikipedia's brief summary of car alarm effectiveness backs up my assumption that everyone just ignores them, so maybe completely disabling the alarm system is the way to go.
posted by EndsOfInvention at 5:05 AM on October 27, 2014

According to our mechanic, there's a problem with the car's factory-installed panic alarm

What was the mechanic's reason for not taking care of it when he/she/they made this diagnosis?
posted by JimN2TAW at 5:39 AM on October 27, 2014 [2 favorites]

A friend of mine has a similar problem with a radio that he refuses to fix, instead he just disconnects the battery completely when the car is turned off. (Opens the hood and disconnects one of the cables from the battery)
posted by czytm at 10:28 AM on October 27, 2014

Indeed. I was going to (upon more information) suggest these two options:

Both would be a better solution than disconnecting the immobiliser/alarm. If you leave the car overnight, just disconnect the battery. It is a good way to stop the battery draining and yet still leave some element of protection.
posted by Brockles at 10:40 AM on October 27, 2014

Response by poster: Brockless: Those are very good questions, which I probably should have mentioned in my original post. Here goes:

I believe it is the alarm killing the battery because that's what my mechanic said was happening. Additionally, when I researched the "symptoms," it seems to be the case. On a side-note, besides the battery being drawn down, the alarm was just starting to go off periodically on its own.

Here's the weird thing about how long the car sits before dying. It could sit unused for literally weeks and will start fine. But drive it even a block after you start it up, turn it off, and when you go to turn it back on, it won't start. In fact, the battery is so drained, nothing will happen when you try to start it. This is the case EVERY time: starts after non-use fine, won't start after immediate second use. I should mention, this doesn't happen every time I use the car, though. But when it does happen, it's debilitating. And it will always happen in cold weather.

As for your specific questions:

1) The battery is a few years old. (However, this problem started LAST summer, and was supposedly fixed - more on this below - and started a few months again after I had it back from my mechanic. At this time, the battery was only about 1 1/2 old).

2) See my paragraph above.

3) Driveway and/or garage. Not sure if you mean does the car or the garage have power? Normally, when not in use, the car has power. Right now it's dead on my driveway from the last incidence (I had to have it jumped to get it back home). The dome light comes on when I open the door and the radio will work along with all the lights, but it won't start. If I try to start it, everything goes dead.

The disconnect switch seems to be a good idea, if this is the problem.

If there's anything else you need to know, let me know. Thank you!

EndsofInvention: Here's where my ignorance comes in. I thought the panic alarm and car alarm were one in the same. I suppose it would be the car's entire alarm. In short, though, I did research the alarm system as a whole and came up with nothing.

COD: I tried the fuse, it didn't work, unless I pulled the wrong fuse! However, there's nothing on the fuse box's diagram that shows the alarm's fuse. I looked that up and found what I THINK is the correct fuse. Know which fuse it is for sure? I'll try it.

JimN2TAW: I figured someone might wonder this when I posted, but I didn't touch on it. This is the second time this problem is happening. It started last year. My mechanic fixed it then, but it's happening again, so you'd assume he maybe didn't fix it or fix it that well. Ordinarily, I'd just take the car back in and tell him the work wasn't right. However, I can't do that in this instance because he fixed this problem (as all the other problems with this car) on the barter system. He's the owner of his garage and I own a company, and we've done some trades in the past. We've reached a point where the system is no longer mutually beneficial. I could pay him or another mechanic, but as I mentioned in the original post, the car is so old, I don't want to dump any real money into it.

Just some additional info that might help: The most recent time the car died was while my wife and I were running some errands. I needed to run into a story real quick, and my wife stayed in the car. We turned the car off but kept the power on, and she was listening to music. When I got back in the car, everything was functioning fine, but when I tried to start it, the car wouldn't start, then everything died in the car.

Thank you, everyone, for responding. Sorry for the long responses, but I figured as much info as I can pass on would help.
posted by LillyBird at 2:11 PM on October 27, 2014

Best answer: My suspicion is that this may be the starter motor, actually. I have had this before with weird and sudden discharging of the battery. My own car last year had this weird thing that gave every. single. sign. of something not turning off in the car as it was identical to the actual symptoms.

This is the case EVERY time: starts after non-use fine, won't start after immediate second use.

This is what makes me think it is the starter. The alarm just ins't capable of pulling enough amps to discharge a healthy car battery (assuming it still is healthy) in the kind of timescale you are talking about without burning up some wires and nothing about a second start soon after a first one would make sense - the alarm doesn't care.

I think the starter motor is breaking down and drawing LOTS of current some of the time it is in use. As this is temperature related that is also more likely. I think it draws so much current that the battery is all over the place in voltage that sometimes it triggers the alarm - the alarm is a result, not a cause.

I think the first start drains the battery down to 'not much volts' which still allows minor electrics to work, but the battery hasn't had time to recover enough to do another MONSTER CURRENT DRAW start so the draw is sufficient that all power goes to the starter to try and turn it (hence everything turning off).

I think you'll need a new starter (which could be pretty cheap for that car) and it MAY have killed the battery doing this (they don't like lots of heavy charge/discharge cycles, especially in cold weather). But you'll be able to get the battery tested once you fix the starter. The more I think about it, the more I am convinced it is the starter.
posted by Brockles at 2:48 PM on October 27, 2014 [3 favorites]

Response by poster: Brockles: Thank you again! I'll check on the starter (daunting task, seeing it seems you have to access it from under the car, which makes me nervous). Hopefully it's that.

One quick question: In researching info on the starter, I came across some items on the solenoid. Could this be the problem instead of the starter? Or in addition to?

posted by LillyBird at 2:21 PM on October 28, 2014

Well, if it's what I think it is then the only checking you can do is to replace it. If the windings in the motor have failed in some way then that will produce it, but if there are no other actual starting issues (slow crank, occasional non-crank) then it's pretty much 'throw a starter in there and see' I'm afraid. It's not something you will be able to wiggle around or clean and make it better. New starters come with a solenoid - change the whole thing.

I've chased an identical issue in a BMW road car and a $150,000 full carbon fibre race car in the last 6 months, incidentally. Both times people were initially convinced it was the battery or some electrical drain and it seems that random weirdness is a starter thing.... The only thing that made it go away was a new starter.

They seem pretty cheap:

I'd avoid the $70 versions unless you really are only going to get it through this winter. A fairly handy person should have very little problems changing a starter as long as you can see it (ie you don't have to take lots of stuff off to get to it. Take pictures of all the wires and bolts beforehand, disconnect the battery and it's probably two or three bolts, a nut for the live wire and a plug. Easy peasy.
posted by Brockles at 2:56 PM on October 28, 2014

This link seems to support it being a simple job:

Seconding the core charge (don't throw away the old one) mention. Often there is a fee on starters/alternators/driveshafts etc that means if you give them the old one back for reconditioning it is less money.
posted by Brockles at 3:02 PM on October 28, 2014

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