I have the original gen1 charger from my 2014 model S (40 amp version). The car has 89k miles on it and has also been charging our model 3 for about 20k miles. Yesterday after charging our model 3 to 100 (two days in a row for road trips), the charger stopped working. I got the 2 red flashes on the front of the charger, which, according to the manual is a faulty ground. I plugged our gen 2 UMC in and the car charged just fine. It leads me to believe the UMC gave out on me. Before I throw it away and buy a new one, does anyone have any suggestions on what might be wrong with it?