To wire your own car alarm, locate a mounting position for the alarm, pry out the trim panel, test the wiring polarity, fix the alarm unit in place, and make the necessary connections. Replace the panels, and test the alarm. Self-tapping screws, wire strippers, a drill, a multimeter and connectors are necessary for this project. Read your vehicle's manual to learn the wiring layout before making connections.
Study the alarm wiring diagram, and choose an installation plan. Identify the desired mounting spot for the alarm. You can install the alarm unit underneath the dash or in the trunk. Use self-tapping screws if you plan to install the unit on a metal surface.
Remove the door trim panel with a door trim remover tool to reveal the switches. Test the switch polarity with a multimeter, and then pass wires to the horn mounting area. If there isn't a hole, drill one into the bulkhead, and fix a grommet in place. Use supplied links to connect the doors and locks. If needed, secure in place any necessary accessories, including the shock sensors, and connect them.
Fasten the horn in place with self-tapping screws, connect the alarm to the positive wire of the horn, and connect the ground wire. Reinstall the panels, and test the installation according to the testing instructions in the alarm manual.