406 interior sensors

[john green]

Hi Guys,
Another little problem on my 406 coupe!
The button to the right of the steering colum which allows you to turn off the interior movemment sensors is permanently lit with a constant red light.
It does not flash when the alarm is set and the car locked and deadlocked. Nothing changes when i press the button either.
I guess its not supposed to do this and wondered if anyone can help
John