The Toyota Corolla has one of the highest theft rates of any vehicle, which makes installing an alarm an easy decision. Installing an alarm in this vehicle requires considerable car wiring skills and the correct wiring diagram. Professional installation is needed for 2007 and later models as Toyota has incorporated a complex data system to thwart would be thieves and unfortunately, most do-it-yourselfers. Read the alarm manufacturer’s manual carefully and identify each of the parts included. Open the hood and remove the positive battery cable from the terminal. Connect the alarm power wire to the positive cable and run it along the firewall to the driver’s side. Find an open area in the engine bay and mount the siren facing the engine. Pull the wires to the driver’s side of the firewall and feed all of the wires through the firewall and into the cabin. Remove the lower dash panel beneath the steering wheel and open the fuse box. Snap the alarm’s door lock module into the existing door