850 alarm problem

[Loz1]

Hopefully someone can point me in the right direction.
Only noticed this problem this morning when we had a heavy downpour followed by hailstone. One of the weather phenominum triggered the alarm off, but no sound. On further investigation, the alarm is actually going off but sounds ill, as if the battery is flat. All indicators are flashing, and once reset, the red led is flashing inside the car. Open the door using the key, alarm goes off but again, really weak sounding and really quiet. I then throught that the alarm is connected to the horns, so something must be wrong with them. Nope, horns work fine.
Anyone got any ideas....as i would like to keep the car as long as possible without some git nicking it in the night (although i could put my two staffordshire in it for safe keeping)
P.S Battery shouldn't be flat, as i use it daily and recently come back from Stansted (450 miles round trip... av 25mpg, heavy right foot in places)

[Loz1]

forgot to mention, its the original (standard) volvo alarm for the 850

cheers

[cameron]

What does the standard 850 alarm sound like?

I dont think mines is right, it works through the car horn, it is a constant horn noise, not a broken noise like most alarms, is this right?

Cheers, Lee

[t5 pete]

Take you car to a local motor spares and get a battey test the alarm horn is near the torque arm near the bulk head

[Loz1]

Looked under the bonet today (in between showers), did a final check with the alarm (set alarm with bonnet open, open door with key), alarm goes off. Poor sounding as yesterday. Turns out its the horn on the bulkhead (thanks T5 pete), the screw-in part of the horn was almost out. Quick job, screw it back in and "Bingo", alarm/horn works. Will check out again tomorrow after a run and possibly use locktite on the treads.
With regards to normal volvo sounding alarm (cameron), mine NOW sounds off short busts off the horn around 1 per second

Thanks again for the help

[t5 pete]

glad to be of help