I have an 02 Astra 2.2 coupe convertible. I set the alarm and everything is fine for up to 8 hours then it goes off. I have read it could be the power sounder. What is this? Vauxhall want £65.00 to put it on the diagnostics. Does this sound right? How much am i looking at to get it replaced / repaired?

thanks for any suggestions.

Gazzak, October 2009

Is the car battery holding its charge properly? If the voltage drops the alarm thinks someone is fiddling with the car.
If that is OK then I'm 90% sure it will be the power sounder battery, the same thing happens, its voltage drops and the alarm sounds.
Often when the PS battery is failing there will be a couple of beeps from the car when you turn the ignition off, did you have this?
The PS is in the passenger side wing (assuming the car is rhd). Remove the wheel and the inner arch liner to access it. Some owners used to split the unit open and renew just the battery, but I dont think you can get the part any more. Easier just to get a new PS.
If you want to get it plugged in to diagnostics best shop around for a better price. Lots of independent garages have the equipment and will be MUCH cheaper, but make sure they know it is the alarm codes you want.

vaux, October 2009