We also had problems with the original solenoid in our 2014 GWV Legend EX built on the MB Sprinter Chassis. It may not be the same as your problem but perhaps our "fix" can help you with your "fix."
We replaced the original solenoid with a White Rodgers Model #124-105111-3 solenoid. It's rating...
Good ideas on the smartphone plastic and epoxy. To avanti: we have the older setup with straps and snaps. We retensioned those and put on heavy felt bumpers. Coffeemaker had same issue with magnet squeak and temporarily fixed it with scotch tape also.
When we took our GWV for its shakedown cruise we noticed an obnoxious squeak that we found to be coming from the bathroom doors. It was caused by the magnets at the bottom that hold the doors shut rubbing against against other. We haven't found a permanent solution yet but the temporary fix is...