NX-481 LED on Motion?


I just received a couple ge/iti pet immune saw motion detectors and I'm concerned they aren't functioning correctly. The detector correctly trips the alarm on motion, but the LED does not light. The LED does howevery light if I open the battery door, so I know it's not broken. Can anyone with a confirm if the LED should light on activity? I'm aware of the three minute lockout. Thanks.
I have the same detector and they are made not to light the LED unless it is in the walk test mode. It saves the batteries etc.