JeffT

iTrader: (1)

Last night whilst working on my MY2001 WRX - the alarm went off for no apparent reason.
I had one front corner jacked up (tilt sensor?) and the bonnet open and was operating an impact wrench off the battery at the time. Had been doing exactly the same previous day with no alarm problems.
Car would start with alarm still going off. After 5 mins of stopping then going off again and making odd little chirps it stopped for good. Never went off through the night and car runs fine.
Just wondering if this is the start of problems. Is there some sort of back up battery that needs replacing? Where exactly is the siren? Is there a re-set button somewhere?
It's standard alarm AFAIK - operates from key fob and also has key pad in car to enter a pin.
Any help appreciated

audioscape

no tilt sensors or shock in the standard alarm unless somone has fitted as aftermarket option. the alarm should not arm if the bonet is open with the sigma there is an option for auto arming it would bleep a few to tell you the times to tell u the bonet is open then go off.
when was the last time you tested your alarms sensors? boot bonet doors ultrasonics.

most people do not test there alarm this is the down fall.
the pin switch on the bonet can cause problems corrosion on the connection to the body, can stop the correct operation of the alarm.

Car Security Expert

Sounds like a bad connection to the siren. There may be a loose plug or wire somewhere.

JeffT

iTrader: (1)

Thank's for both replies. I'll check pin switches today.
Any idea where the actual siren is? If I could find it I'll check for loose wires.
I did a search and have seen mention of sirens failing or battery back-up pack failing. Had this on a previous car - could this be an option?

audioscape

possible battery back up failure but doubt it
siren i have seen in a couple of different locations front drivers side by air filter or by the master cylinder

JeffT

iTrader: (1)

Thanks Audioscape - think I've located siren. Underneath cover for windscreen wipers below and in centre of windscreen. Will have a better look tonight. Alarm does not seem to sound at all now (tried setting alarm using remote but left a door open - normally this will make siren chirp several times but it was silent) so this would support the loose or broken connection to siren theory.
Thanks

JeffT

iTrader: (1)

Had siren out last night - didn't split it as I didn't want to damage it. You could just hear a slight buzz or groaning noise from it as thought there was very low voltage trying to make it go off.
Alarm is now dead. Does main alarm run from car battery? And if you then tamper with alarm and disconnect battery, siren will still run from back-up battery in siren?
Car seems to start OK and imobaliser working fine but I just feel there are more problems ahead.
Should I try and split siren or just replace it or give up and try Auto Electricians

audioscape

sounds like siren has water damage replace it then should all be ok. phone scorpion they are the distributors for sigma now.