With after-market electronic car products prevalent, more than ever you need to tap into the car's electrical harness. You can wire stereos, burglar alarms, auto-starts and power accessories of all types permanently into the auto's 12-volt system. After you strip back the ends of the wire, you face several options for connecting two wires together: wire nuts, barrel connectors or soldering guns.
Strip about 1/2-inch of the plastic housing on both ends of the wire to be joined, using a wire stripper.
Twist the ends of the wire together into a point, using your fingers.
Insert the pointed end of the wire into the end of the wire nut. Begin twisting the wire nut in a clockwise direction. You will feel it begin to grab the pointed end of the wires. When it does, continue twisting until it becomes tight and hard to twist.
Insert one end of the stripped wire into one end of the barrel connector. Insert the other end of the wire into the other end of the barrel connector.
Force them into the center until the ends meet or slightly overlap.
Smash and collapse the metal sleeve inside the barrel connector using the jaws at the end of the wire strippers. Focus on smashing from the center of the connector and work your way out to the end.
Twist the two ends of the stripped wire together with your fingers into a point.
Apply the tip of an already hot soldering iron to the point. Hold it there for about three minutes. Apply solder to the wires while still holding the hot tip of the soldering iron to the wires. When the solder melts, apply more until you saturate the twisted ends of the wires with wet solder. Remove the soldering iron. Let the solder cool for five minutes.
Wrap the ends of the wire with electrical tape. Wrap down the wires about one inch, then double back, overlap and wrap the soldered joint again.
