How to reset the car security system on my 1993 Gs300 Lexus

Hello, i'm not sure there is any way to "reset" a factory security system. An aftermarket system would only be reset with a remote control. I would suggest you reach out to a local shop near you that can give you some guidance: http://repairpal.com/lexus-within-10-miles-of-grand-rapids-michigan-49503