96 Turbo R Alarm Isolate Switch in Glovebox - Settings?

[Scotty2]

Today I stopped to buy some antifreeze and oil at local motor factors. Came out and pressed the "Disarm" on my fob but the light on the dash did not go out, and the car wouldnt start. The central locking occasionally operated from the fob but the imobiliser stayed on. I disconnected the battery and connected and tried again - no joy. New battery in the fob- No difference. Called auto -aid and started to wait. Listening to the radio, I noticed the clock was a few mins out, so opened the glove box to set the clock. I then noticed and remembered the alarm switch. Moved it to position 1 and bugger me the immobiliser went off. Called off auto aid and headed for home.

I couldn't find any info in the manual or a quick internet search, so can anyone describe what the positions of the switch actually do?

[buyer&seller]

Has your car got intrusion sensing? It's at the back of my mind that it may be something to do with that, is it three positions?
If three, I'm thinking 1) Full alarm 2) Turns the sensing off 3) Switches the alarm off but the remote still operates the locks.
It's many years now since I've looked at one or explained the controls (I sold these cars when they were new) so I could well be wrong.

[Scotty2]

Not sure on the "intrusion" option.
I've left it at "1" as there have not been any alarms or failures to disarm since being moved.

[alabbasi]

If your car is a 96, you might have a nicad battery in the module which is located behind the dash or a nicad battery in the siren which is in the right side wheel well. Those usually go bad and leak all over the circuit board. If's smart to remove it and and relocate it from the module where it's accessable.