96 corolla master window lock button does not click on

I never used the master window lock button located to the right of the door= lock/unlock. When i wanted to lock the switch so no one in the car can use= the windows, it does not click on like a pen; when i press it, it goes bac= k up. I think its missing a spring or a mechanism but not sure, anyone know= what i am missing and where i can buy one? Its a waste to buy the whole th= ing because everything else still works.