Crimp-on wire connectors provide a simple method of connecting wire terminals without the need for the installer to learn how to perform soldering techniques. Though extremely simple, one must understand how to use a crimping tool properly to perform the job so the connector isn't damaged and a solid connection is made. The key to reliable results is to ensure that the connector being crimped was designed for use with the wire gauge onto which it is being crimped.
Cut the wire to the desired length and use a pair of wire strippers to strip away the necessary length of insulation from the wire end onto which the crimp-on connector will be installed. The wire should be stripped so that the bare metal end of the wire goes all the way through the barrel of the crimp-on connector.
Slide the barrel of the crimp-on connector over the bare metal end of the wire, and then pinch the entry end of the barrel and the wire firmly between the forefinger and the thumb of one hand so the wire doesn't move or otherwise pull from the connector until crimped. Pick up and hold the crimping tool in the other hand.
Place the crimping jaws of the crimping tool onto the barrel of the wire terminal and squeeze firmly, observing the barrel as it collapses onto the bare portion of the wire inside of it. The interior metal walls must squeeze against the bare metal portion of the wire in a fashion that the wire won't pull from the connector.
Inspect the connector after crimping to make sure none of the metal interior of the connector is visible through the exterior plastic insulation. Though terminals are manufactured to prevent damage during proper crimping, occasional damage may result. If metal is visible through the outer plastic insulation, cut the connector off and crimp on a new connector.