are you sure you don't have power locks? when you unlock the car, do both doors unlock? then you do, there is no button for the locks in e-30's. You can buy a kit, i think the company is Autolock or Steller is another, they advertise in Bimmer, The Roundel and other mags, Also i think ther sold through BMP. Even if you don't have, what is called central locking, they still have kits that will work