alarm led scanners in 06 scion xb?

I have a Varad alarm LED Scanner, which has 3 wires have to connect, they are ground wire (Black), a constant 12V (Red) and one is for the Alarm system accessory output or ground output when armed (Yellow).

I know where to connect the black and red. But where should I connect the yellow one if I want the Scanner activate when I press the lock button at the remote?

Mine is a 06 xB and i want to using that without an alarm.

Thanks,

what kind of alarm do you have ? the yellow is ground when arm .when ever you arm the alarm it activates most alarm systems have them .

He is trying to connect it to the factory keyless entry system.   There is 1 way that I know of to do this.  It requires a reed switch and a magnet.  If you insist on it only being on when the doors are locked, you will have to remove the door panel and attach a magnet to the lock mechanism, and mount a reed switch somewhere that the magnet will activate it when the door is locked.   An easier way to do it, with the light being on whenever the ignition is off would be to use a relay to provide ground to the LED module.     85 and 30 need to be grounded.  86 accessory wire.   87A to the LED module.  When the key is on acc you will have no LED.  Ignition on  no LED.  Key off    module will be active.

since that yellow wire is looking for a ground input to activate...... you could connect the yellow to the vehicles ignition wire, since it will rest at ground when the car is off. whats the difference if it is activated everytime u shut your car off, whether its locked or not?