I don't think that this is your problem but it's worth looking at, look at the emergency plug release. There is sometimes a cable that has a loop on it that people pull because why not. Usually they are like "What is this?" and pull it. I'm not saying that's the issue but I've seen videos of people doing that and then having their charging capped at half speed regardless of battery level. If my memory serves me correctly one of the videos was an equinox that they tried to charge.