I've noticed this a few times before - that is, whenever I've had to disconnect the battery, the alarm goes potty for the next few days. The last time I did this (to change the alternator) the alarm would sound for no reason. At the time I suspected the bonnet switch/sensor. Eventually, the alarm stopped going off for no reason and all was well. Today I fixed my ICV, and now it's happening again. Except this time it's much worse. Now the alarm 'pips', even when the car is unlocked and the alarm is deactivated!
If I leave the car unlocked, after about 5 to 10 minutes it starts 'pipping'. By pipping I mean the alarm horn sounds very very briefly, about 4 times a second, for about 2 seconds. Like a rapid series of gentle taps on the horn. The indicator lights flash too, so I know this isn't a 'car horn' problem, but an alarm problem.
I took the car out for a 20 mile 'warm up', and reset my audio lock and re-programmed the electric windows, as you're meant to do, and on the road the car was fine. But as soon as I got back this happened:
- I locked the car up and waited
- within a minute the alarm sounded
- I used the keyfob to unlock the car
- the alarm stopped sounding, but the pipping thing started up almost immediately
- I got in and started the engine - the pipping continued
- I drove the car a few hundred yards - the pipping got worse
- I stopped the engine and got out - the pipping stopped.
- My car now sits with the battery disconnected again
- Disconnect the car alarm so that it can't do this
- Disconnect the horn, so the alarm can't sound (only flash)
- Disconnet the battery each time I park up (can you imagine that in Tescos carpark?)
- Set fire to the car
I think the alarm's horn is different to the 'in car' horn, so could I just find the alarm's horn and unplug it? I know the lights would still flash, but if it righted itself in a few days then I'm sure the neighbours wouldn't care about a few nights of occasionally flashing lights