alarm keeps going off

UK forum for general and technical discussion about the Z3 roadster
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kp
Joined: Fri 10 Apr, 2009 14:35
Posts: 62

  Z3 roadster 1.9
Location: york

alarm keeps going off

Post by kp »

Hi There, Wonder if anyone has any suggestions for me to try, when i lock my car up using the remote it can be left for some time then the alarm will go off, The last few days i have had to lock it with the key. Thanks :head:
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Ian_C
Joined: Sun 10 Dec, 2006 20:10
Posts: 2415

  Z3 roadster 2.8
Location: Lytham St Annes

Post by Ian_C »

Try disabling the ultrasonic sensors inside the car and see if the problem disappears.
Current...1998 ///M Coupe
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Previously...1997 Z3 2.8
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trigg35
Joined: Fri 18 Sep, 2009 20:24
Posts: 239

  Z3 roadster 2.2i
Location: newquay

Post by trigg35 »

had that with mine and found a post on here re bonnet sensor.my one used to go off after 10 - 20 mins perhaps to do with the car cooling down.not sure.anyway i disconnected the bonnet sensor - problem solved.wish i had done it sooner as i spent six months locking the car with the key.its fairly common i think and the part is about a fiver if you want to replace it.i just left it disconnected.its not like its hard for a thief to break in given its a soft top with a plastic window.
indizee
Joined: Wed 24 Mar, 2010 08:26
Posts: 315

  Z4 roadster 2.5i
Location: Nr St Neots

Post by indizee »

I found a thread that explained how to disarm the ultrasonic sensors by pressing the alarm indicator light then locking the car. However, I found my button's spring mechanism had broken. So now i remove the indicator light cover and turn it round to disconnect the electrical connection it makes inside.
Present : Grey Z4 2.5 conv
ex-Cosmos Black 2.8
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kp
Joined: Fri 10 Apr, 2009 14:35
Posts: 62

  Z3 roadster 1.9
Location: york

thanks

Post by kp »

Thanks for quick reply's will have a look at it over the weekend.
wella_fella
Joined: Thu 04 Jun, 2009 09:57
Posts: 130

  Z3 roadster 2.8

Post by wella_fella »

Good luck!

I have had alarm issues for over a year!!

Im just having to lock it with the key!

I have disarmed the interior sensors - still went off

disconnected the bonnet sensor - still went off

looked for a boot tilt sensor - havent got one!

:head: :head: :head: :head: :head: :head:

ARGGGGGGGGGGHHHHHHHHH!!!!!!!!!!!!!!!!
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Robert T
Site Admin
Joined: Mon 12 Jun, 2006 10:35
Posts: 10171

  Z3 roadster 1.9
Location: Cheshire

Post by Robert T »

For those still pondering over the Z3 alarm system, there are only a limited number of things that can go wrong with it. Check each of the sensors in turn:

* Bonnet switch - these seem to have a short plunger, which has been superceded by the one off the X5 in the parts catalogue - you can either fit the longer plunger version or adapt the existing one with some padding.

* Radio switch - wired in parallel with the bonnet switch. It relies on the prong on the back of the radio depressing a microswitch in a little cradle. Some aftermarket stereos don't fit this properly and in other cases it has not been refitted, hence the bonnet switch won't trigger the alarm.

* Interior sensors - there a couple of types, but most UK zeds have ultrasonic sensors, which can be prone to false alarms. Try setting the alarm without these active - press the lock button again on later alarm or press the LED on the earlier type. Note that the official BMW cure for a dodgy ultrasonic module is to replace it with a microwave one!

* Door switches - these are peculiarly located in the back of the door catch at the back of the door opening (most cars have a plunger at the front). These can wear and eventually not make proper contact. If this is faulty you will usually find the interior light behaves erratically.

* Boot switch - this is located in the boot lock in the boot lid - it is NOT the plunger things either side. There is a conical piece in the lock plate on the car that goes into a corresponding hole in the lock and depresses a microswitch in the bottom. Fairly evidentially the wiring for this goes through the know weak-point of the boot lid wiring - so broken wires in there can wreak havoc.

* Tilt switch - located in the left-had well behind the rear wheel - you'll need to have the trim off to find it. The well often fills with water and this can cause problems with the tilt switch. The tilt switch is disabled in the same was as the interior sensors.

The later alarm logs codes telling you which sensor (or approximately which in the case of the bonnet and radio switches) tripped the alarm and these can be read back with appropriate equipment. You may need to clear the codes and then read them again after is has gone off, as we have all managed to trigger the alarm accidentally by opening the boot with the key!

The later alarm can be unset by putting the key in the ignition and turning it to position II. This is handy if your remote battery goes flat as it uses only the car's own power to read the immobiliser chip in the key.

The earlier alarm cannot be unset except by some very nefarious means involving the removal of the glovebox. It can however be silenced by means of a small key in at the siren. This only turns off the siren, the indicators will continue to flash.

One final note. Microwaves do seem to set off the Z3 alarm. I have twice triggered the alarm on my zed simply by working on my other car (which has a microwave alarm) right next to it. It has also been noted that minicab radios are very good at doing the same thing - usually at about 2am.

Hope that helps. At some point I might type that up as a knowledgebase thread.

Cheers R.
Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
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Brian H
Joined: Tue 16 Dec, 2008 19:55
Posts: 2505

  Z3 roadster 3.0i

Post by Brian H »

Great Write up Robert, below is a liitle more info for the earlier alarm models.
Robert T wrote:The earlier alarm cannot be unset except by some very nefarious means involving the removal of the glovebox. It can however be silenced by means of a small key in at the siren. This only turns off the siren, the indicators will continue to flash.
For cars with the BMW IIIG EWS alarm (the ones with the separate house brick) you should have a Emergency over ride proceedure card with a PIN code. The card tells you how to disable the alarm without the remote fobs.

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HTH
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Geoff H
Joined: Sat 08 Nov, 2003 12:03
Posts: 713

  Z3 roadster 2.8
Location: Wellingborough

Post by Geoff H »

I did post that info back in April http://www.zroadster.net/forum/viewtopi ... ht=#235057
yours is a clearer photo, but as in the other post its no good unless you have the personal code to enter
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kp
Joined: Fri 10 Apr, 2009 14:35
Posts: 62

  Z3 roadster 1.9
Location: york

cheers

Post by kp »

Thanks for all the advice given, i will eliminate one by one and hopefully get it sorted
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