How to wire a 12-volt plug
Manufacturers of portable electronic appliances supply their products with 12-volt adaptors and patch cords that enable those appliances to be used inside vehicles in order to increase their product's utility and marketability.
A 12-volt automobile plug is standardised in the United States by the "UL standard 2089," which covers plugs and cord patch cords that insert into cigarette lighter receptacles.This type of plug is easy and convenient to use, but it can break down once in a while. Learn how to wire a 12-volt plug and never allow a defective one to stop you from using your favourite 12-volt appliance.
Buy a 12-volt plug from a local auto parts store. Observe the plug and notice the retractable metal nipple at its tip and the two retractable metal fins protruding on each side of its cylinder. The tip is the positive conductor, and the side fins are negative conductors of the 12-volt circuit.
Hold the plug on the corded end in one hand. Hold the other end with your other hand and twist the plug hand counterclockwise to unscrew the cap from the plug's cylindrical body. Remove the cap along with the metal nipple at the tip of the cap from the plug's cylindrical body.
Remove the holding screw along the cylinder using a screwdriver. A cigarette lighter plug is typically split lengthwise along its centre into two identical halves. Disengage the two plastic halves and slowly open the cylindrical body to reveal the metal fins (negative conductor) inside, including a small spring that pushes the retractable metal nipple. The metal fins inside the cylinder are sandwiched in place by the two halves of the plastic cylinder. Observe carefully and remember the order in which the metal conductors and spring are arranged.
Cut the tip of the power cord of your 12-volt appliance flush using diagonal pliers. Strip off 1/2 an inch from the tip of the positive and negative wires connected to your appliance, using a wire stripper. Loop the stripped end of the positive wire (red, or black with white stripe) around the crimp-type connector at the base of the metal nipple (positive terminal). Crimp the wire by placing the connector with attached wire between the jaws of your pliers and squeezing the pliers' handles tightly. Cut any excess wires using diagonal pliers.
Loop the stripped end of the negative wire (black, without stripe) around the crimp-type connector at the base of the metal fins. Crimp the wire by placing the connector with attached wire between the jaws of your pliers and squeezing the pliers' handles tightly. Cut any excess wires using diagonal pliers.
Replace the metal connectors and small spring between the two halves of the plastic cylinder. Replace the holding screw on the cylinder to fasten both halves of the cylinder together. Screw the plastic cap along with the metal nipple onto the cylinder. Make sure that the positive and negative terminals and wires do not come in contact with each other. Insert the cigarette-lighter-type 12-volt plug into a 12-volt receptacle and turn on your appliance.