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[Terry_Seyforth]

Hi just lately the alarm goes off without reason, not sure why, it seems to be late in the everning/morning, I did remove the cd and did notice when the alarm went off the light near the cd changer was flashing red, which I prosume is a indication that there is a theft, but the problem is that it went off on a couple of nights before I removed the cd changer/tape, are these cars prone for the alarms going off, I have had this car for about 6 weeks now, it only seems to have been playing up recently ?

   any ideas thanks.

[Marks DTM Calib]

Hi just lately the alarm goes off without reason, not sure why, it seems to be late in the everning/morning, I did remove the cd and did notice when the alarm went off the light near the cd changer was flashing red, which I prosume is a indication that there is a theft, but the problem is that it went off on a couple of nights before I removed the cd changer/tape, are these cars prone for the alarms going off, I have had this car for about 6 weeks now, it only seems to have been playing up recently ?

   any ideas thanks.

The common cause is the bonnet switch, the mounting gets bent by hand fisted mechanics.....so my first steps would be.

1) Inspect the switch mount and make sure its vertical (its back right of the engine bay mounted by the passenger suspension turret), you can simply un-plug it to prove its this.

2) If with the bonnet sensor disconnected the alarm still sounds, try pressing the alarm button before locking the car, this disables the ultrasonic sensors.....which then helps to eliminate these from the investigation.

I suspect it will be the bonnet sensor though which as said can go off if the switch is not vertical because the bonnet expands and contracts with the changes in temperature.

Other possibles are

a) Failing power sounder battery

b) Failing main car battery

But lets start with the simple stuff first.

[Kevin Wood]

There are a couple of common causes to look into:

1) Bonnet switch. Sometimes the bonnet warps as it heats / cools and this can set it off if the switch is a bit sensitive. If you simply unplug the switch and try it for a few days- if it doesn't go off this is your problem.

2) Power sounder. This is located under the plastic scuttle cover and provides backup if the vehicle's battery is disconnected. It's a siren module with internal batteries that degrade with time and can leak over the circuit, causing false triggers. Do a search on here and you will find information on how to locate and disconnect it.

3) Internal sensors. Try pressing the button on the dash before setting to disable the ultrasonic and movement sensors.

4) There is, IIRC, a wire from the alarm to the radio to detect radio removal. This needs to be grounded if you change the radio, for example by connecting it to the radio chassis using a tag.

Kevin

[Terry_Seyforth]

  well this is getting technical....... I have had a cam belt changed so there has been a machanic under the bonet, I will look at this first, and unplug it, to see if this remedies the problem. if it does do i buy a new one ?
I will try this first.
I am working away today but my partner said it went off today when she got out and left it for a minute to go in the shops.
I am home tomorrow and will try the first step.
You know I spoke to my partner today and she said she loves this car, which I do love driving too, I do to all be it that its very firsty.
I am although getting a bit concerned as I have only had the car a short while and finding many niggley things, that do cost a lot of money to buy.
oh well I suppose when you have a classy car you pay the price.
Will let you know step by step of progress.
What would i do without your knowledge, scream most prob.
Thanks a lot. speak to you soon.

[Terry_Seyforth]

Just a update, dont think its the bonnet alarm.
What I have noticed though is there seems to be two types of alarm on this car, you got the normal horn alarm and a high pitch alarm, its the high pitch alarm thats going off, I went to the shops yesturday, didnt put the alarm on as I left the car it just started going off, the high pitch, I tried the key to switch the car alarm off, although I didnt put it on, but it just continued, it goes off when it feels like it, 3.30 am, or maybe 15.30 pm not predictable ?

So can we ID the high pitch alarm, does this link to anything in particular ?
Thanks all

[Terry_Seyforth]

Well it just wont stop going off now, i have disconnected the bonnet and it still went off, i have had to take the fuse from the battery to stop it.
si after the bonnet what sensor should i try next please.
Thanks

[Terry_Seyforth]

I have now disconnected the light above my head to the front center, I think this has a sensor in it ? am I right, I will see how this goes.

[Terry_Seyforth]

3) Internal sensors. Try pressing the button on the dash before setting to disable the ultrasonic and movement sensors.
could you explain step by step please ? :-/

[Andy B]

3) Internal sensors. Try pressing the button on the dash before setting to disable the ultrasonic and movement sensors.
could you explain step by step please ? :-/

The button on the dash with a man running away from the 3 curved lines   is used to temporarily disable the ultrasonics so that you can leave your dog/sleeping child etc in the car without upsetting the alarm. If you press this button before you leave the car & before you enable the car alrm ie lock it you're checking whether or not it's the interior ultrasonics that's setting off your alarm. I would think that when you unplug the centre courtesy lamp (later car with ultrasonics inbuilt? ) you'll upset the alarm further cos it won't be able to see the 'sonics.

[Terry_Seyforth]

how many sensors are there inside the car, ultrasonics ?
I removed the sensor because i was advised to remove the supply to the bonnet sensor, it still went off, so wasnt that, but you are saying removing the light ultrasonic will disrupt the curcit.  Well I put the fuses back in and removed the light sensor, not gone off yet, but it does seem to wait till hours in the morning, its quite regular time in the morning, about 3.30 am  

I will try the button as you suggested, I will press it and then get out and then put alarm on, this will leave the sensors off, but the only problem is there is no visual sign saying the sensors are off, just push button once then,  try I shall.
someone mentioned the power sounder ? I think I may have ruled this one out as when the fuses are pulled the alarm doesnt go off, and the power sounder has its own battery ? Am i right ?
Can you for the thick person, thats me, the key has boot, and two more uses, one to open doors, and the other locks, but does this one once pressed again enable something else. I was told to press once to lock and then again to enable alarm ?

[mkaminski100]

Is it estate? Then try to disconnect back window sensors (brown lines on the window with 2 connectors). Mine was going off because of that, and as TheBoy checked it wasn't the sensor, but problem on the line (connection, broken wire.). Same symptoms, alarm was going off at night, 3-5 am. I don't know where exactly problem is, and have more important thing to fix in my car at the moment, so these sensors are disconnected now.

[Terry_Seyforth]

No not estate thanks.
The person who said lets start here, can I have some more help please  .
I disconnected the light sensor, didnt go off till 1.30 am this morning, so it isnt the BONNET or the LIGHT sensor, helllllllllllllllllp what next. :-/
My friend said last night that sometimes the air can come through the vents and the sensor can pick it up, but the sensor was removed so that rules this out I suppose  :-/

[Marks DTM Calib]

Ok....other possibles are.

1) Failing power sounder.

2) A sudden power drain.

Air through the vents is VERY much a long shot, this will only cause trouble if it actualy casues something to move i.e. a childs sun shade etc.

So, next step.

a) Unplug the pwoer sounder which is under the drivers side scuttle area (large ish black item).

The ideal would be to get the fault codes read.

[Terry_Seyforth]

Hi I have heard about disconnecting the power sounder, but what will this prevent working in the future, I read somewhere that they have replaced the power sounder battery, this is the link what they said you could use but feel a bit unsure, http://www.cellpacksolutions.com/Search_Data_Sheet.asp?ID=UO120364
So next step is remove power sounder. I await your reply.
Is this not just stopping the alarm and not finding what the problem is ?

[Terry_Seyforth]

Where can I get these read, fault codes, vauxhall I suppose. Arm and a leg