There is a push button switch attached to the bottom of the tray below the radio. It is not visible unless you remove the trim plate to reveal the radio. My car is a 93 300zx convertible. Thanks in advance for the help.
Brian

 

Sounds like it's aftermarket. Maybe fog lights or something. If it's not aftermarket then check your owners manuel

 

DONT PUSH THAT BUTTON! Is the self destruct button a rare option on those convertibles

 

I think it was installed at the factory. It is not accessible unless you remove the trim to remove the radio & I couldn't find anything in the manual about it. Who knows maybe it is a self destruct button! But if it is it needs to be a little easier to get to.
Brian