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Mon Dec 12, 2005
17:55
I will preface this by stating I only have experience with the factory VW alarms on A3 VWs (that's 1993-1998 Golfs and Jettas, and Cabrios of similar (but not exact) vintage). I'm not sure if any A2s ever came with factory alarms... perhaps some Corrados, but I don't know anything about them if that's the case.

Once again, I have noticed a trend in the search engine queries that lead people to this site. It seems a lot of folks are looking for info on the factory Volkswagen alarm; particularly, deactivating it and finding out why it goes off when the battery is reconnected.

Okay, I think I know what the majority of the people looking for info are *really* after... disabling the alarm altogether because they don't like it when it goes off. Most common is the "my alarm goes off every time I disconnect and then reconnect the battery, or every time I jump start the car". As most VW geeks know, this is the way the alarm is designed - it is intentional. The best thing to do when reconnecting the battery or jump-starting the car is to have a friend standing ready to insert and twist the key in one of the door locks as soon as the alarm goes off. Inserting the key in one of the doors and twisting it in the unlock direction is the official method for deactivating the alarm on these vehicles, unless you are lucky enough to have a keyless entry system (in which case, you have a little button on your key fob that will silence the alarm).

I'm afraid I can't endorse bypassing the factory alarm system (not that my endorsement is actually worth anything). First of all, it's not a trivial task. The system was purposely designed to be inaccessible and difficult to disable and/or remove. The Alarm system is also integrated with the central locking system. Not only is it difficult to bypass or remove the factory alarm, but it really shouldn't be necessary (unless you are replacing it with an aftermarket system). Disconnecting the battery isn't something that should have to be done on a regular basis, and likewise for jumpstarting. If you're needing to jumpstart your vehicle all the time, you'd be best off fixing the problem rather than killing the alarm. A consistently flat battery is typically the result of a battery that will no longer retain a charge, an electrical problem that is keeping the battery from being charged, or an electrical problem that constantly draws power from the battery even when the car is off.

The other problem you may have with the factory alarm system is that it sounds when it shouldn't. I had that problem on our 96 Golf. The alarm would sometimes fail to deactivate when the doors were unlocked. When the alarm did deactivate, it would reactive itself again once the engine was started, and so opening the door again to get out of the vehicle would cause the alarm to sound. It was incredibly frustrating, and it took a whole night to troubleshoot. We started by checking the wiring that runs into the front doors below the a-pillar (those accordion-like rubber boots that run between the front of the front doors and the main body of the car). There are switches in the front door locks that activate and deactivate the alarm system. When you lock a door, the alarm becomes activated (meaning that it will sound if it senses an event). When you unlock a door, the alarm deactivates and you can open doors without the alarm sounding. My first thought was that there was either a nearly-broken connection in the wire providing the deactivation signal, or a short involving the wire providing the activation signal... or perhaps some combination of both. Everything seemed to check out, though - the switches were still intact and functioning correctly, and the wiring going into the body of the car from the door was just fine. After studying the wiring diagrams in the Bentley book for quite a while, it seemed that the central locking system control module was related to the alarm system. The central lock module itself is located in the rear of the car, in the luggage compartment. It will be encapsulated in a 2 piece styrofoam shell. In Jettas, it is on the driver's side of the car, up against the side of the luggage compartment (pull the carpeting back the goes up that side, and you will see it wedged in the body panel above the fender). In Golfs, it is on the passenger's side of the car, just next to the tail light (you will have to pull back the carpeting going up the side of the compartment in order to see it). The vacuum pump for the locking system (the locks are vacuum actuated) is contained in the same housing as the electronic control module, so don't be surprised when you see a vacuum line attached to it. If you need to disconnect the vacuum line, squeeze the base of the connector with a pair of pliers, and you should be able to work it free. If you are having funky alarm problems, then try disconnecting the electrical connections going to the central locking module and see if the problem goes away. If so, then the locking module is your problem. That's what my problem ended up being. Opening up the module housing, we found some water inside it, and the circuitry was badly corroded and burnt. You may want to buy this part used if you need to replace it. New ones are $280 and upward, as of this writing.

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Date: 07/16/06, 11:40:54 PDT
From: owens
Comments: I'm not real sure what fuse it is, but when we overworked the fuse for the cigarette lighter in a 97 Golf, it blew and the alarm system would not shut off for anything in the world. We took it to a local WheelWorks place and they simply replaced the blown fuse and did the unlock trick on the driver's side door, which reset the alarm to its normal state.

Date: 09/03/06, 11:45:29 PDT
From: Ed
Comments: The post on the 97 Jetta Factory alarm problem worked for me!! How my problem started was first of all I had a bad battery which complecated the issue of the alarm going off and not being able to disarm it. I tried everything. First trying the passenger door by turning the key which did not work. Then looking under the dash above the fuse block where all of the fused are and I could not see where the alarm module might be so I was ready to give up and try to get the dealer to tell me something or take it in to them which for me is a last resort I hardly ever do that because I like to try and solve the problem myself. I have also a bad ignition switch which I thought might be the problem, the dealer sometime ago said it would eventually go out but so far it has not. I bent my key a litlle bit and I push up or down on it to make contact in the tumbler. Also I thought it might be the clutch as it also makes contact with the ignition being a manual transmission. Also in the trunk the door lock module is in the trunk behind the carpet that has a plug which I disconnected because another site said that module also has a vacum line attached to it and an electrucal plug and could be the problem, That module is in a syrofoam two piece case. The other site that told me about that had a bad module there and it is about .00 dollars and his had moisture in the module and it was all corroded. I unplugged the electrical plug but that was not my problem. So anyway after reading this post here I determined that my cigarette lighter inside light and clock were not working at all. Now before I discovered what I will tell you I could not get the car alarm to shut off period every time I connected the new battery it came back on. And as you probably know now from other posts on other sites it does drive you crazy and your neighbors as well plus I had to do all the disconnecting of the battery myself quite frustrating not to have help when your running around the car. Also under the hood is where the alarm horn is and I lifted the grill and shoved a rag in the mouth of the horn to muffle the noise it did help. Onward here now I knew that my fuse was blown with the lighter,clock,and inside light but did not realize that it might have something to do with resetting the alarm. Anyway again after replacing the fuse I connected the battery and the alarm still came on driving me crazy still, but this time again I ran to the passenger door and tried the key to turn it to unlock position to stop the alarm and by holding it in the unlock position the windows electric on mine came down and NO ALARM how happy was I for before I could not start the car or anything so try what I said. The Module in the trunk was diconnected so it will start even with the module disconnected but when you do connect it it does make the alarm come back on and you just have to go to the door again and disarm the alarm again anyway I hope anyone working with this problem has luck with my post here thanks to the one who originally posted. My email is aercon2@yahoo.com let me know if this works for you GOOD LUCK ED

Date: 11/14/06, 19:28:44 PST
From: Darren
Comments: Hope you can help. Just bought a 96 Jetta. In replacing the battery I noticed another calbe coming off the negative terminal hanging loose. What is that supposed to be bolted too??? Thanks.

Date: 02/03/07, 15:00:06 PST
From: Dave
Comments: So I have a similar problem. The alarm won't seem to deactivate. I tried unplugging the control module electronics, as well as the vacuum line, and nothing changes. It is strange, when I turn the key to the normal unlock position in the drivers door, I get the soft honks that I would normally get when I lock the door. When I turn the key, I can hear the lock control module working (when its plugged in) but the door locks don't move. The interior lights turn on, clock works... etc. But the car will not start. I was only able to push start it to get it home when I was stranded. Any suggestions??

Date: 02/03/07, 19:22:30 PST
From: max
Comments: Hi Dave, are you sure that the alarm is not deactivating? For example, when you had to push start it to get it running, then alarm would have sounded when you opened the door to either get in or out of the vehicle if the alarm were not deactivating. You may have more than one issue causing these problems. Also, you say that you can hear the vacuum pump in the control module running yet the locks do not actuate - that sounds like either the vacuum pump is running but not able to create vacuum (meaning it's worn out) or there is a leak somewhere in the vacuum lines that feed the lock actuators. You can check both pretty easily - disconnect the vacuum line at the central locking module, and go fetch a friend. Have one of you use the key to either lock or unlock all of the doors while the other person holds a finger tighly over the vacuum connection on the module. If you don't feel vacuum, then the pump isn't doing it's job anymore. If you do feel vacuum, then check the vacuum lines. My favorite trick is to suck on the end of the line a little bit and then immediately put my tongue over the end (yeah, I know - kind of gross) and if the vacuum holds then your tongue just stays stuck to the end of the line. If it turns out there's a vacuum leak somewhere in that mess of lines, then it could be a little bit of a chore to find exactly where the leak is (there may even be more than one), but that's at least a start. You say that when you unplug the central locking module, nothing changes - but that seems impossible. If nothing else, your central locking will stop working altogether (you'll only be able to operate one lock at a time with the key) with the electrical connector to that module unplugged. As far as your alarm behaving "backwards" (giving the activation beep when you unlock), I would start by checking the wiring going from your locks to the large connectors in the door jambs, and then from the door jamb connectors to wherever those connections lead (mostly to the central locking module and alarm module). Look for shorts between the wires, as well as breaks. They are pretty easy to check with a multimeter and the wiring diagrams from the Bentley manual. The wiring in and around the doors and door jambs as well as the switches for the locks themselves are known to be a little bit of a problem as the cars get older. Anyway, using the wiring diagrams and doing some well thought-out checking with a multimeter should let you see for sure whether the correct signals are being sent to the central locking module and the alarm module. It is the alarm module that is responsible for immobilizing the car and activating/deactivating the alarm. It is possible that the alarm module is bad; however, that seems to be an incredibly uncommon problem. More likely is a problem with the signal(s) being sent to it (wiring or switch problem). The alarm module is designed to be incredibly difficult to access (for obvious reasons), so it's no fun to replace them.

Date: 04/19/07, 18:05:27 PDT
From: greg
Comments: my problem has been with my back windows....i try to send them down and the alarm ingages as i am driving or without the key in the ignition. Any suggestions

Date: 04/19/07, 19:48:31 PDT
From: max
Comments: Have you tried disconnecting the central locking control module to see if the problem goes away? If it does, then you've got a bad module. Those are very similar symptoms to what I had (except for the windows - our car has manual windows), and it ended up being the central locking control module (in Golfs, they are prone to water damage due to their location near the hatch and passenger side tail light). That central locking module is tied into the alarm system - so a malfunction in either the central locking module or the alarm control module itself can really cause some screwy things to happen.

Date: 08/10/07, 15:22:02 PDT
From: Teh Beef
Comments: I have a 97 VW Golf that has been sitting in a garage for a few months... it was at my mom's house and since it was sitting there, she decided to unhook the battery. I'm trying to reconnect it and the alarm goes off as soon as the terminals are connected to the car... I tried turing the key in the lock and even in the ignition and nothing works... any suggestions?

Date: 12/13/07, 12:06:29 PST
From: Carlton TDI 2000
Comments: Well Gentlemen, My alarm would not deactivate. Everytime I started the car, opened a passager's door the alarm would go off, lights and horn. It was like I was steeling my own car. I reviewed the blogs here and just deactivated the horn. I lived with this for about a week. My remote key wouldn't even work. Then just out of the blue, I manually unlocked the trunk using the key, got in the car and the alarm did not go off. Then I thought maybe the remote key would work, so I shut off the car, and tried to lock and unlock the doors. Everything works now. What did I do? Nothing. On 2000 Jettas the control module is underneath the windshield on the driver's side, in between the engine and cabin. You have to remove the cowling that is just under the windsield wipers. That is where the horn is also. Some things you just can't explain.

Date: 03/05/08, 11:49:54 PST
From: Kohl
Comments: hey, i am having the alarm problem, with the 95 jetta i just bought. i was wondering wut i can do because i cant even start the car becaseu my alarm is always on and when the last time it went off it wouldnt stop so i unplugged the battery and it all stated a cold morning and it turned on my i was going down the road. turning my key wont eenen turn it off if u have any suggestions please shot me and e-mail. at kohl_zehr2000@yahoo.com

Date: 04/15/10, 21:15:22 PDT
From: Shannon
Comments: Hey, im not sure if anyone can help. I have a 98 VW Cabrio and it has a factory alarm. The past few weeks we've had a lot of rain and the alarm wasnt beeping when I locked the doors all the time anymore and the light wasnt as bright. Today when I ran to the store and it worked fine. When I went to leave, the car wouldnt turn over and the alarm started going off. The odometer and clock kept fading in and out and then they were fine. The lights and radio still worked though. I tried unlocking and re-locking the doors with the key, unlocking the trunk, etc. Every time the alarm kept going off. I was in the car and didnt even lock the doors, and it would set, and the light would flash. I tried to disconnect the module behind the tail light. I pulled the electrical wires and what I believe is the vacuum line (considering it was the only other wire there) and the alarm still went off when I tried to start it and the car still wont start. Any other ideas of how to fix it, or what it could be? Any would be appreciated. Thanks.

Date: 06/25/10, 02:20:36 PDT
From: Tim Smith
Comments: We have an 02 Cabrio that the lock was not engaging consistently. Our keyless remotes have not worked for years, so we always use the key. Yesterday it would not unlock. Then the key rotated either 180 or 360 deg in the door lock and now will not turn at all. Additionally, the power lock switches in the doors do not unlock the doors either. Needless to say, the alarm is consistently engageds when we start the car, turn it off, or open the doors or hood. Sounds like the Locking Module, so where is that located on the cabrio? thanks

Date: 06/25/10, 06:23:22 PDT
From: Max
Comments: The 02 Cabrio may have a different alarm / power lock setup than I was talking about in this blog post. Although the 2002 Cabrio is on the A3 platform, it was being built at the same time as the A4 Golfs/Jettas and so VW may have updated the power lock system and alarm system with those put in the Golfs and Jettas at the time. That being said, I can try some educated guessing. In your case here, I rather suspect that your problems are caused by a mechanical issue with your door handle/lock assembly. The part of the door handle/lock assembly that goes inside the door has a sort of paddle shaped piece attached to the end of the lock cylinder, and this paddle engages switches for locking/unlocking the door as well as arming/disarming the alarm. The paddle piece is prone to breaking off after years of use, and when this happens the lock cylinder will turn around when you turn the key but none of the switches will be hit, and so the locks/alarm will not operate. The fact that you mention the lock turning 180 and 360 degrees tells me that paddle piece probably broke (or possibly, the lock cylinder itself or the piece that the paddle engages with may have broken), allowing more movement than normal - and the broken off piece could have then jammed it up, preventing it from turning at all. If this were a Golf or Jetta, I would suggest using the passenger side lock to get around this problem for now - but I believe that the Cabrio only has a lock on the driver's side, correct? Your interior power lock switches not functioning are probably due to the alarm being activated - it would make sense to disable the power lock switches on the inside until the alarm is deactivated. The thing to do is remove the door handle assembly to verify whether this is the problem. After 1999, the Cabrios started to use different door handles, and I am unfamiliar with the newer type - but the previous type were a real pain in the neck to remove and reinstall. It also seems to be difficult to find replacement driver side door handles for this newer type of handle - you may have to get it from the VW dealer. If nothing else, if you take it apart you may be able to manually trigger the switch to get the alarm to deactivate. With the alarm deactivated the car should be driveable again. You could also try disconnecting the alarm module, but on these later systems the car may not even start with it disconnected - on top of that, I am unsure where the alarm module is located in your car. If it is not behind the carpet somewhere in the luggage compartment, then it is probably buried up behind the dashboard somewhere. I hope this was helpful - good luck!

Date: 06/25/10, 06:23:42 PDT
From: Max
Comments: The 02 Cabrio may have a different alarm / power lock setup than I was talking about in this blog post. Although the 2002 Cabrio is on the A3 platform, it was being built at the same time as the A4 Golfs/Jettas and so VW may have updated the power lock system and alarm system with those put in the Golfs and Jettas at the time. That being said, I can try some educated guessing. In your case here, I rather suspect that your problems are caused by a mechanical issue with your door handle/lock assembly. The part of the door handle/lock assembly that goes inside the door has a sort of paddle shaped piece attached to the end of the lock cylinder, and this paddle engages switches for locking/unlocking the door as well as arming/disarming the alarm. The paddle piece is prone to breaking off after years of use, and when this happens the lock cylinder will turn around when you turn the key but none of the switches will be hit, and so the locks/alarm will not operate. The fact that you mention the lock turning 180 and 360 degrees tells me that paddle piece probably broke (or possibly, the lock cylinder itself or the piece that the paddle engages with may have broken), allowing more movement than normal - and the broken off piece could have then jammed it up, preventing it from turning at all. If this were a Golf or Jetta, I would suggest using the passenger side lock to get around this problem for now - but I believe that the Cabrio only has a lock on the driver's side, correct? Your interior power lock switches not functioning are probably due to the alarm being activated - it would make sense to disable the power lock switches on the inside until the alarm is deactivated. The thing to do is remove the door handle assembly to verify whether this is the problem. After 1999, the Cabrios started to use different door handles, and I am unfamiliar with the newer type - but the previous type were a real pain in the neck to remove and reinstall. It also seems to be difficult to find replacement driver side door handles for this newer type of handle - you may have to get it from the VW dealer. If nothing else, if you take it apart you may be able to manually trigger the switch to get the alarm to deactivate. With the alarm deactivated the car should be driveable again. You could also try disconnecting the alarm module, but on these later systems the car may not even start with it disconnected - on top of that, I am unsure where the alarm module is located in your car. If it is not behind the carpet somewhere in the luggage compartment, then it is probably buried up behind the dashboard somewhere. I hope this was helpful - good luck!

Date: 01/28/18, 16:37:25 PST
From: Bruce Tiffany
Comments: Just bought a 1999 GTI MK4 for my son. It came with 2 knife keys. I replaced the battery in both remotes. and the alarm and or auto locks will not work. I've checked the fused labeled with a key symbol. The light next to the door lock is not on. any help would be great
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