Had alarm going off at random yesterday, coincidentally also when my rear washer had stopped squirting water on to the rear screen and into inside of hatch door instead. Suspect water/dampness in some sensor is causing the alarm to trigger. Not got time to take off door trim and investigate, will look at it later this week. In the meantime I pulled out the fuse and no more alarm going off. What I am wondering is if I just leave the alarm fuse out will there be any problems apart from car being less secure. Is there  a back up battery in the alarm siren which might not be getting charged when the alarm circuit fuse is removed and which might be set up to make the siren make a noise warning of low battery voltage, rather like domestic smoke detectors do when the battery is about to run out. Anyone on the forum taken one of the alarm sirens apart and can share info on how they are set up?

Thanks in advance.

John Archer

Edinburgh

insurance won't pay out if it's nicked. Just sayin'

I took the alarm siren thingy apart and found the battery inside had rotted the circuit board , The battery in it  has a shelf life of 4/6 years I think and the alarm thingy should be replaced every 6 years.. Approx £90 last time I priced one. With me the alarm didn't go off just the flashers flashed. Now I deadlock it ( two presses on the key fob ) and it does not matter about the alarm siren. 

I took the alarm siren thingy apart and found the battery inside had rotted the circuit board , The battery in it  has a shelf life of 4/6 years I think and the alarm thingy should be replaced every 6 years.. Approx £90 last time I priced one. With me the alarm didn't go off just the flashers flashed. Now I deadlock it ( two presses on the key fob ) and it does not matter about the alarm siren. 

You do know that two presses on the key fob disables the deadlocks and interior motion sensors, don't you?

I suspect that your rear washer is leaking into the tailgate latch wiring. If you have your car diagnosed they can check out the last 4 alarm activations to confirm it's the rear latch wiring triggered the alarm.

Edited 12 January, 201511 yr by FLAPPERJACK7

You do know that two presses on the key fob disables the deadlocks and interior motion sensors, don't you?

Yup, was gonna say! This is what I do when the dog's in the boot so he doesn't set it off.

As far as I'm aware, it does the same thing Mike.