I have the 2017 Premier Volt. The charge ring was ordered with the car, installed at the factory.
Low and behold, I had the same problem. Ring light would not come on when opening the door, wouldn't come on all the time when taking the charger plug out. Eventually, even that stopped working.
The dealer is supposed to be trained in the VOLT and its peculiarities, but I found that both the service writer and the service tech didn't have an idea of how it was supposed to work and were telling me fantastic stories of how it was supposed to work.
Look at the manual, I believe it tells you something about how it should work.
If you get out of the car after you stop it and open that door, it should be ON.
It will flash in unison with the dash light as it charges and when completed, it will go out.
When you pull the charge plug, it should come on and go out when you close the door.
Mine was finally replaced by the dealer but I had to find information of how it was supposed to
really work and give it to the service writer, who gave it to the service tech before they would
do anything.
Don't believe everything the service tech or the service writer tell you, they have been wrong
many times on how things in the VOLT work.