68 barracuda turn signal switch

They aren't all the same. Some of the aftermarket switches are junk. There have been several threads about tweaking the little contacts etc.., trying to make a cheap switch work like it should. Daniel Stern Lighting can hook you up with a quality switch.
Turn signal switches come with wires but not the harness connector. You may find it easier to replace both male and female OEM connectors with more modern molex connectors. Good luck with it.