Help On Starlet Airbag

[Xon]

my is a 1996 model

I have no sign of the lamp airbag lights nither on ignition. but the bulb exists because i've dismanteled the dash. i 've contacted local agent of toyota and been told that the airbag will not light because it is a mechanical system on 1996 models. then why bother making a bulb if it will never be used ??? does anybody knows how can i know if the airbag is working or if the bulb must be lit ? 10ks