Use a professional crimper and electrical moisture sealant to make quick, solid connections in auto wiring.
Strip the insulation so only the bare wire is inside the connector. Then make a single 5/16-in. crimp on each side of the butt connector.
Cut a section of moisture sealant to cover the entire connector and a 1/2-in. overlap on each end.
Then double it over and squeeze it together with your fingertips.
Crimp-on wire connectors work well if they’re crimped properly (a 5/16-in.-wide crimp) and sealed (usually with heat-shrinkable tubing). But most cheap crimping tools only make a 1/8-in. crimp, so you’d have to make four of them for a simple butt connection.
Invest about $25 in a professional crimping tool (OTC No. 4497 from www.sjdiscounttools.com). Then buy a roll of electrical moisture sealant (3M No. 06147; about $20 from amazon.com). Then just follow the steps in Photos 1, 2 and 3.
Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.
Avoid last-minute shopping trips by having all your materials ready ahead of time. Here's a list.