Horn sounds when I pull the key out of the ignition

Exactly as the title says. When I shut the car off and pull the key out of the ignition the horn goes off and does not stop. Locking and unlocking the car with both the key fob and the key in the door do not change anything. The first time it happened I was playing around with the key while the ignition was on (maybe even running) thinking I hit a panic button or something and somehow got it to stop when I removed the key. I cannot duplicate that now and it goes off the second I remove the key and stops when I insert the key and turn the ignition. I unplugged the battery for the weekend and put it on charger so no issue there. I tried searching and there are lots of horn issues but none like mine. Car starts and runs just fine. I�ll address some things that came up in other searches or what I think might be relevant. Alarm works as expected, one press silent but lights flash, two presses and alarm horn honks and lights flash. Ended up pulling the horn fuse which works but obviously I would prefer to have a horn and know why this is happening. I have a momo steering wheel but used an NRG hub so no modifications to the clockspring. With the fuse in and key in the ignition the horn works fine with the key in the off position, the on position, and when running. Both doors lock and unlock with the key fob and the key in the door. The windows crack when opening the doors. Electric trunk latch and fob work as well. Same with the boot lid. Interior lights all function as expected. Battery is from 2017 and holds a charge just fine. No parasitic draws on the battery as it held a charge fine over a few winter months. Factory radio that is working as expected. Horn never sounded off at unusual time such as when turning, braking or accelerating. Wondering if anyone has run into this. Don�t want to just throw money at parts that are not needed. I am thinking ignition cylinder but again I haven�t seen anything to confirm that will solve my problem. Not sure why the key being removed from the ignition would cause that as it is not a normal symptom for an ignition switch failure that I can tell.

Sounds to me like the first step is to replace the ignition switch!

All right, bringing this infuriating problem back. Finally got around to changing the ignition switch and same problem. When the key is removed from the ignition the horn sounds and will not stop. I have to pull the dual horn fuse for it to stop. That means I have no horn while driving. Sure would be nice to have a horn. There are no other symptoms and it just started randomly doing it one day. Nothing had been touched. Once I turn the key on the horn stops. I can turn the key off and it does not sound but once I pull the key out it goes off. No pressing of the key fob to activate or deactivate the alarm or turns the key in the door changes anything.

Year of car and which horn blows when key is removed? The alarm horn or the dual car horns and I read that you pulled the car horn fuse. I would be happy to search the schematic given the info requested above.

2002 c2, the dual horn. That is the fuse (b3) I pull to get it to stop. Horn button works fine when fuse is in and key is turned. When fuse is removed key fob will still lock and unlock. Alarm horn beeps when doing so. Don�t remember it doing that before. Can confirm with the fuse removed the alarm still functions. Definitely not the alarm horn. The alarm horn is much quieter.

Disconnected horn button and no change so it is not related to that. Tried locking and unlocking everything manually.

Quotes source post: 20187931

Usually the honk is related to an open circuit in the alarm system. Got a scanner like the Durametric? Run a check and see if it identifies where it's coming from by the thrown codes.

The honk is not related as it is known to occur when you pull the fuse. No diametric, regular obd2 scanner does not pull anything.

When you say �the horn sounds and will not stop�, do you mean an unending honk, like a roadrager laying on the horn? Or is it a repeating pattern of �honk-pause-honk�?

Exactly, as if I am jut laying on the horn. Does not stop. Happens only when the key is pulled from the ignition. I cannot get it to stop unless I put the key in the ignition and turn it at least one click.

Quotes source post: 20187942

The standard OBD2 reader is not going to scan the alarm module hence the need for one like the Durametric. Personally, I've had this problem too. The problem ended up being a malfunctioning lock mechanism. Once replaced, the honking stopped and the system armed the car properly. Again, the best advice I could give you is use a proper scanner to help pinpoint the culprit. Electrical issues can be a nightmare to solve otherwise. It could be something simple like a bad IR motion sensor above on the sunroof panel.

The alarm functions properly. Just does the beep because the fuse is pulled. When I arm it and open anything the alarm sounds as it should. What lock mechanism? As in get a new ignition key and tumbler and change out all the keyed locks?

Bad alarm sensors wouldn�t that activate the alarm horn not the dual horn?

Quotes source posts: 20187961, 20187919, 20187931

Aaahhh... ok. Sorry missed that part. Since the horn sound is coming from the dual horn in the front and not the alarm speaker located next to the battery, then I would say there is definitely something wrong with the ignition switch. Another common failure point. Even though you've replaced the switch, something else is causing the horn to trigger. Any idea if someone replaced the steering wheel?

Yes I replaced the steering wheel but did so with the NRG hub to keep the clockspring intact. The only thing I did was hook up the jumper the remove the airbag light. I had been running the wheel for a long time with no issue. Horn button works when the fuse is in. Disconnected the horn and it did not change anything.

Quotes source post: 20187970

Only speaking from experience with my 996s...On my '03, if the alarm was triggered, the front horns would blast along with the lights blinking. Guess the idea is to draw attention. Normally, alarm problems are handled with quieter chirps that came from the alarm speaker.

cab or hardtop?

This sounds like a sick joke. Hope it�s fixed!

I do not think it is alarm related. There is no issue with the alarm other than the beep which should be due to the removal of the fuse from my understanding. No lights flashing, no alarm, nothing unusual other than the dual horn going off indefinitely only when the key is removed. Only turns off when I reinsert the key and turn it to at least accessory.

Quotes source post: 20188035

hardtop

If I had to guess, your clockspring probably has some sort of short circuit. I would start diagnostics by checking the wiring at the horn relay with a multimeter.

Your horn button is causing a short circuit. I had this same exact issue after installing an aftermarket Momo wheel. My Momo horn button became loose after some driving and triggered the same exact symptoms that you�re describing. I would take a close look at the horn button and reinstall it making sure the button is making good contact with the ring that holds it.

Not to play devils advocate but the horn functions just fine when the fuse is in and the key is on. I never removed the clockspring. Horn is not shorting out otherwise it would go off when the key is on too. Or at least when driving or turning. It is a normal car until you remove the key. Ignition made sense but new one is doing the same thing as the old one.

Quotes source post: 20188090

I removed the horn button from the equation by removing it entirely, and unplugged it, and the horn still goes off when I remove the key.

Does the horn sound when you turn the key to position 0, but leave it in the ignition cylinder?

No, only goes off when the key is physically pulled out of the ignition. Will not turn off by putting the key back in the ignition, turns off by turning the key to position 1.

Quotes source post: 20187986

Reinstall the OE steering wheel and see it you can replicate the problem. My guess is the OE steering wheel will NOT create the horn issue. Try it and report back.

I can try it but I know already that will not likely do it the NRG hub does not change anything like a momo hub does. I specifically chose it because it is a jumper spring to defeat the airbag light and that�s pretty much it. Did yours go off only when you removed the key? Button works, clockspring works, turn signal defeat works, alarm works, everything works. Key removed horn goes off unless I turn the key or pull the fuse. Put the fuse back in and the horn goes off again. Super weird.

Quotes source post: 20188101

You cannot just remove the horn button. The circuit needs to be closed. Removing the horn button alone will tell the system that it�s an open circuit causing the issue.

Quotes source post: 20188150

What is this jumper spring that you used? Is your car a manual or tiptonic?

Sorry jumper wire. You have to run a wire to make the car think there is an airbag otherwise the airbag light is lit. Technically it is a resistor. If it failed it would just make the airbag light illuminate. The airbag light did not come on as part of this. The steering wheel has been in a while. Like I said the horn functions as normal when the iignition is on. Ithe horn only comes on when the key is removed from the ignition.

How well is that resistor insulated? Any possibility that the resistor has a bit of exposed wiring?

I would snip the damn wires off the horns and carry an air horn when I need to annoy others.

I've never had a 996 horn/steering wheel off, but the schematic shows a pretty simple circuit. Positive feed comes from fuse B3 to the horn relay which is #10(second row far right. mounting block has numbers embossed in it) in the Relay Support 1 which is above the fuse block behind the side kickpanel on the drivers side. The horn button provides the ground when closed(normally open interlock) to ground point 4. If it was my problem first thing I would do is swap the relay out to see if it is janky.(verify part number before swapping relays) It is part# 141 951 253B which is also the same as the AC/heater relay #18 which is bottom left relay or any of the other relays in the bottom row(fan relays.) Other than that you are picking up a ground for the horn circuit. If you jumped the horn button wires together that could be your problem as that provides the ground to blow the horns any time B3 fuse has a positive feed. I know none of the above explains the actuation of "continuous on" horns when the key is removed. That just doesn't make any sense to me. I would have to look again but I think b3 fuse is hot all the time. It was late for me last night and I might have missed that but don't think so. I'm just spitballin' here...

Any update? Curious if you have had a chance to check further.

No update, I have not had a chance to check anything. I think I am going to start with checking the relay. Makes sense it would be hot all the time as I believe the horn works even without the car being on. Perhaps the relay is opening (or closing) when the accessory power is removed. If that doesn�t work I might start pulling the wheel although that makes less sense to me as the horn and everything to do with the horn, stalks, airbag light and the clockspring work as normal. Something is happening when power is pulled from the car so if those items were faulty I would expect something to not work or for the alarm to be going off, not the dual horn.

Keep us updated please.

Will do, not a lot of spare time in my life so anything beyond a relay might require me to hold off. I have a million project so it is difficult to prioritize this nuisance when the car is fine other than not having a horn due to the pulled fuse.