Zafira alarm problem - *pinky*

I have an 02 Zafira and over the past week the alarm has been going off, usually middle of the night, early hours of the morning, its driving me (and no doubt my neighbours) mad.

I have been told by some really helpful people that this is a common problem/fault yet no one can tell me what is causing it or how to rectify it.

I have had the battery tested and its fine, there is nothing loose in the car that could be triggering the sensors, so I am at a loss as to what to try next.

If all else fails could I remove the fuse that relates to the alarm without it affecting anything else in the car?

I welcome any suggestions and ideas.

Thank you.
Zafira alarm problem - Dynamic Dave
The most common fault is the bonnet pin switch. Check to see if it hasn't been knocked and is out of alignment.

The other common fault is the back up batteries in the sounder fail. But you usually get some warning that they're imminently going to fail by 4 small beeps.

Last resort, the alarm *should* store a fault code which can be read out with the appropriate test equipment - usually Tech2.
Zafira alarm problem - SpamCan61 {P}
One other thing to try is closing all the air vents before locking the car, in case warm air currents are triggering the sensor. Oh, also make sure the seat belts are reeled right back in, in case any slight movement after locking is triggering the alarm.
Zafira alarm problem - *pinky*
Thanks for your replies.

Will check the bonnet catch as suggested and try closing the air vents. I am certain its not seatbelts as after the first time i double checked them, I used to have an impreza that was notorious for the seatbelts moving and setting off the alarm!

It has been suggested that it could be vibrations from vehicles passing it but I don't think that will do it as it has never done it before - however next doors huge van reversed next to it this morning and that set it off? I have shook the car by its roof bars and had it all rocking and this didn't trigger the alarm.

Its got me flummoxed.

Thanks again.
Zafira alarm problem - Dynamic Dave
I have shook the car by its roof bars and had it all rocking and this didn't trigger the alarm.

This of course isn't the same as the windows getting vibrated at a certain frequency by next doors huge van.

Several years ago there was only one thing that falsely set off my alarm on a previous car; that was a neighbours mk3 Ford Escort XR3i as it drove by. Nothing else ever set it off.

I *doubt* very much if the internal sensors are picking up seatbelt movement of airflow from the vents. From previous experience of Vauxhall alarms, the sensors aren't that sensitive. Yes, they will pick up a window breaking by air pressure difference, but if the windows are wide open, you have to frantically wave your arm through the window before the sensors will pick up the movement.
Zafira alarm problem - Statistical outlier
Try turning off the interior sensors - that was the problem on my previous car. Most cars have this facility so that you can leave dogs / kids in the car.
Zafira alarm problem - PeterRed
I've got a 2004 Zafira. You can turn off the interior sensors by pressing the 2 interior light buttons (above the mirror) before exiting and then setting the alarm within 10 seconds. A light comes on in the central dash for those 10 seconds.

Had the same problem with night time alarms a few weeks ago. Disabling the interior sensors had no effect. I took it into to the dealer under warranty and they claim to have 'fitted a new alarm siren'. This has fixed it.
Zafira alarm problem - Ruperts Trooper
Failure of the "powersounder" is a common problem on Vauxhalls with factory-fit alarms. The back-up battery within the siren unit fails. 4 beeps are given when switching off the engine when this battery is starting to fail. If the powersounder isn't replaced, the alarm is eventually triggered, after a few weeks.

I have to replace the powersounder on my 2000 Astra every 2 years. It really ought to be on the service schedule but Vauxhall claim they sometimes last longer!

The unit is about £55 and can be fitted diy if you adhere strictly to the "how-to" on but it may be best to leave to a Vauxhall dealer as faulty fitting will need "re-programming" at the dealer anyway.

Ask Honest John

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