I'm installing a stereo head unit and don't have sound. This blue wire comes from the included harness and is the amp control wire. The control wire on the other connector at the unit also says amp control and isn't connected to anything. I'm assuming I have to connect the two wires and this thing (plus heat shrink wrap...?) will help. I'm unsure if I should use this or cut and strip the wires and find some wire nuts. How do I use this connector, (if it even is one)?
That is the male side of a bullet connector. You need to either get the corresponding female connector and crimp it on the other wire, then plug them in, or cut it off and use a butt splice to join the two wires.
Thanks! Solved.