Bloody alarm!!!!

[adsvx220]

My dads 2002 320 convertible alarm is driving me mad. He keeps it in my yard behind my house as it saves him parking it on the road outside his house across town. The alarm goes off very randomly in the early hours of the morning and during the day. Not good when I have to run outside in my boxers and dressing gown to turn the flaming thing off when I'm half asleep.

I have bashed the roof with my hand trying to replicate a cat jumping on it we have even shook from side to side but we cant set the alarm off.

Can anyone give me any ideas on what of if there's a problem with the alarm system.

Cheers

Adam

[M3Charlie]

How often does he drive it? Is the battery going flat?

[NiceCupOfTea]

Anything metal near the internal sensor? Is there a spider living in it?

[adsvx220]

He only usually drives it on weekends when he doesn't need his van so not very often.

Could a spider trigger the alarm then. Will have a look tomorrow to see if there's anything metallic that could interfere with the sensors.

Adam

[TheEnd]

Try disconnecting the bonnet switch, and another one is press the lock button twice and it'll deactivate the interior sensors.

[Luca Brasi]

Unplug the bonnet switch, problem solved.

[Neil.D]

Replace the bonnet switch first. Very cheap and easy.

[adsvx220]

Will try the bonnet switch aswel then. Could be the culprit with 3 separate posts saying the same thing.

Adam

[anonymous-user]

Had same issue recently and did 2 things

- charged battery which was low
- unplugged bonnet switch

I have now re-plugged bonnet switch so it would seem the cause was the low battery

[essayer]

Take everything out of the central cubbyholes and storage pockets between the seats.

[NiceCupOfTea]

essayer said:

Take everything out of the central cubbyholes and storage pockets between the seats.

My mobile in the centre console used to set off my Clifford when I went to pay for petrol!

Why does everybody reckon bonnet switch? Do they fail that often?

[blondini]

Bonnet switch is a common failing on the e46. Diagnosis free of charge by disconnecting and it's cheap and easy to replace.

[aizvara]

Funnily enough I've just had the same thing happen twice this evening on my e46. Not sure what caused it, but I've removed a variety of coins (some just added) from the tray.

So far its not done it again, but this could be coincidence.

[blondini]

aizvara said:

Funnily enough I've just had the same thing happen twice this evening on my e46. Not sure what caused it, but I've removed a variety of coins (some just added) from the tray.

So far its not done it again, but this could be coincidence.

If you had a vert I would say it was the coins. Any other model it's just a coincidence as only the vert has a microwave interior sensor that would be affected.

[anonymous-user]

RC1 said:

Had same issue recently and did 2 things

- charged battery which was low
- unplugged bonnet switch

I have now re-plugged bonnet switch so it would seem the cause was the low battery

About 24h after reinstating the bonnet switch the alarm went off randomly again. I'm going to to replace it!

[aizvara]

blondini said:

If you had a vert I would say it was the coins. Any other model it's just a coincidence as only the vert has a microwave interior sensor that would be affected.

Ah, thanks; that resolves the confusion I had regarding how an ultrasonic sensor in my saloon was being affected by coins in the car.

Must have been something else, then. Hopefully it wont happen again.

[dr_gn]

Replacing the bonnet switch solved my random car alarm problems ('02 330i Saloon).