Carrera 2 cab alarm issues - how do you disable it?

My factory alarm has been giving occasional problems for a while but now is being a real pain. It goes off quite often, usually at night. The other night it would not stop, even went off with the car unlocked and the drivers door open! I had to disconnect the battery in the end. The only clue to the problem is that when problems have occurred the alarm siren emits a crackling sound all the time, varies in volume and intensity. It sound like it may be a faulty unit in which case I would rather disable it altogether, anyone know how to do that without messing up anything else? Any other suggestions welcome? Ritchie

Is it the siren or horn that goes off? If it's just the siren open up the bonnet, take off the battery cover and the RHS plastic cover as you look at it. Under there just next to the battery you'll find a black casing with round-ish red siren. This can be unplugged. Apparently this will send a fault code to the ECU but at least your siren won't go off. This has a downside though, when you take it to a specialist to get a diagnosis all they will see is that fault code over and over again, well at least that's what OPC told me. In order to get it properly diagnosed you need to take the car to them as soon as the siren goes off....!!!!!

The alarm siren and tilt sensor are an add-on for the UK to meet Thatcham requrements. When they go wrong, they don't tend to throw up a fault code. If you disconnect the siren, or tilt sensor, make sure you switch the ignition on (as you do when removing the battery), otherwise the siren will go off.

Bloody fibbing Chiswick!

Another thought occurred to me after reading the title of your thread - "cab". First thing to do is check under the passenger seat and see if the carpet is damp...... What year is the car, BTW?

Cab alarm & HRW? Thanks for the tips guys. It is a 98 car, one of the early ones. 60k on the clock Checked under the seats, all dry. Thinking about it only the alarm siren goes off, not the flashers, the red LED under the screen looks normal so maybe it is only the siren that is faulty? and as you say I could disconnect it or replace it with a good 2nd hand one. I assume it is not an "intelligent" siren is it? Are you saying leave the ignition on while you unplug the siren? On a different subject I dont suppose anyone knwos of common faults with the HRW and heated mirrors. The switch light comes on and the fuse is OK but none of the heating elements come on. Any tips there? Thanks Ritchie

It would be worth getting a diagnostic check done soon, because you might be barking up the wrong tree. The reason I asked the MY, is because early 996s like yours had the tilt sensor mounted near to the alarm siren. It has a whitish-clear plastic box. These are notorious for filling with water. A faulty tilt sensor definitely won't give you a fault code, because they didn't allocate one to it. Yes, leave the ignition on while you disconnect the siren and/or tilt sensor. You might get a double-beep from the alarm horn when you lock the car, but it will stop when you reconnect another unit.