Lets start with year, make, and model.
If you don't have one, go over to MyMopar and download a factory service manual, or "closest you can get". You may have to settle for Plymouth vs Dodge, etc
I have factory manual for valiant wiring. All seems good there. I bought sockets that have their own ground. It is 1967 Barracuda fastback. I put meter to plug for socket and get fluctuating reading (set at voltage DC) which seems like should be good. I will double check soct or use one from other side to see if by chance got bad socket.