Alarm will not stop going off!

A

anevil_devil

Member
Hi Everyone!

I have noticed that there are several threads on the forum about the bonnet sensor causing the alarm to keep going off so that was the first thing i tried and it didn't work. Yesterday I was cleaning some green gunk that had formed around the bottom of the roof (where it meets the rubber seal) and my alarm went off. Thought nothing of it (was actually quite glad to know it works) so just unlocked the car and it stopped. Finished what I was doing and locked the car again, no problems. A couple of hours later after being out I could hear a constant high pitched beep. Turns out it was my car. Instead of intermittently beeping it is just constant. It went off about 3 times last night. I have tried locking the car manually etc and it now even goes off when the car is running! Anyone got any ideas what the hell is wrong with it?! I have now resorted to disconnecting the battery to shut it up (i am going to look for the fuse next).

Somebody please help me! :D

Just incase you need to know it's a 53 plate 3.0i roadster.
 
welcome along...

there should be no need to disconnect the battery :o Simply locking the car using the key in the door will not engage the alarm.

As for your problem - I've no idea :(
 
i had pretty much the same problems as you, however once i unplugged my bonnet sensor the beeping stopped.

since thats obviously not the issue with yours, id try uplugging other sensors (if you know where they are) or you might be up for a trip to the dealer and paying money for them to read out a fault code!
 
My 53 plate's alarm went off randomly so after researching here and trying the bonnet sensor to no avail I went with a new battery and it seems fixed.

It did not go off whilst the car was running though so I guess you can't take too much from this! Locking the car with the key also stopped mine going off, and it only ever beeped intermittently. I realise now I have been of no help, sorry!
 
Bonnet switch has to be the first thing to look at as it's also the cheapest if it doesn't cure.
 
Ok, so I thought I'd post a progress update (or lack of).

I eventually found the correct fuse (why don't bmw stick a fuse diagram with the fusebox?!) for the alarm system and unplugged it. Problem solved except for the fact that my remote central locking doesn't work so I have to lock the car with the key. A couple of days later it was a nice day when i got back from work and the fuse had been unplugged for a few days so I thought I'd try and solve the problem myself so I parked the car on my drive with the roof down and plugged the fuse back in. 5 minutes later the alarm was going off. Ok so next thing is I unplugged the bonnet sensor again. 30 minutes later and the alarm still hadn't gone off so I thought great, put the roof back up and still didn't go off. EPIC!...... Not quite. It was fine for 2 days then it does what it always does here in wales and rained! A LOT! I parked up in work went in and 10 minutes later my mate came in and told me my alarm was going off (yet again!) and it had by this point become the consistent noise again not the intermittent beeping. So is there a leak somewhere possibly? Anyone else had any experiences like this? I am still avoiding being charged a fortune by my dealer to not fix the problem at the moment.

Thanks! :D
 
Any progress on your alarm problem yet. I have the same problem mine started going wrong when I found water in the battery well ( leaking through the brake light in the boot) I have removed the fuse, but like you can't afford a trip to the stealers at the moment.
 
I know this might sound stupid but when you say battery do you mean the car battery itself or a backup battery for the alarm? My thoughts being that surely I would have some other issues if the car battery was playing up?
 
Just thought I'd ask to see if anyone had any ideas... I've checked the battery and the indicator is green which should mean it's ok, but is there another way I can check how well the battery is working? Like the voltage that can be drawn or something?
 
I've got the same problem with my 53 plate 2.5litre z4. Except mine does not sound the siren, just flashes the indicators for a while. I'm suspicious that the previous owner got fed up with it going off and disabled the siren somehow. I've already tried changing the bonnet sensor with no luck. I have noted it seems to go off after I've been in the boot. Maybe the boot sensor? Is there one? Can't seem to find one.
 
I've now had my battery tested and according to that it is fine. Not really sure what to try next tbh, is begin to sound like quite a common issue. I've now had everything from just the lights flashing with no siren to the constant siren that won't stop even when the car is running!
 
Did you ever find the cause for this?

I’ve got a similar issue - not bonnet sensor

Double locking doesn’t work
Locking with the key doesn’t work
Removing Fuse 30 doesn’t work
I haven’t had the alarm go while I’m driving
Only alarm sound, no hazard lights

It’s driving me crazy every time it goes off 😂

Next port of call for me is check the tilt sensor behind the rear wheel

2006 2.0l E85
 
Where in Wales are you, if in the South your welcome to join our Zedshed Cymru Whats App Group we have in South Wales based in Newport.
Enthusiasts from Z3 and Z4 Forums, we have access to full diagnostics so saves paying garages to do it. Owners buy parts and jobs get done on our cars, left to the individual to make a donation to the shed running costs whatever they think is fair, I don't charge for my time.
PM me with your phone number if you want to be added in to the Group.
 
jonnya93 said:
Next port of call for me is check the tilt sensor behind the rear wheel
Click to expand...
The tilt sensor is in the center console. The alarm horn is behind the rear wheel. At least it is on my 2003.
 
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