After connecting and disconnecting my Roadster UMC from my Roadster maybe 2,500+ times in the past seven years, the slide switch on the connector stopped working, seeming to only push forward about 1/4 of the way. The blue halo light around the charge port did not come on. The issue was that an internal brass threaded "o" ring had become loose with repeated use. Taking a look inside the end, there is a black rubber gasket or grommet that can be seen around the outside of the inside cylinder: That "O" ring may be removed by prying out with a small screwdriver and it looks like this: Once that rubber "O" ring is removed, there is a brass threaded "O" ring beneath it. The issue with my connector was that this brass threaded "O' ring had become loosened to the point where it was no longer tight. The looseness also exhibited itself by the outer shell of the connector being able to move excessively in an up and down direction (as opposed to also twisting back and forth like it is supposed to do). Taking a small screwdriver and using it in one of the three indentions (see below for the indention) to tighten the brass "O" ring solved the issue of the connector not working. Once the brass "O" ring was tightened, the outer shell was no longer loose, and the switch worked again.