I had trouble with a couple items due to wire nut crimps that weren't done right. One was the right speakers and the other the water pump. Drove me nuts. They looked and tested OK, but they would intermittently fail. Of course not when I was checking them. Finally just released the crimp and found one of the wires was not inserted all the way when crimped. Twisted them together (as should be done) and installed a new wirenut. No problems since. I probably have another one in one of the ceiling lights. It works most of the time except when you really need it
. One of these days I'll remember to take it apart and fix it.