I too, am on my third, the first two had problems from the beginning. I was told by Tesla that heat was the problem that most often causes UMC failure, and I installed a small fan above where it lives in my garage (no HPC) to keep the UMC body cool. So far, so good, after a bit over a year. Mind you, the first one (that came with my CPO Roadster) was labelled as "shop use only" (?), the second was a remanufactured one, the one I have now was brand new.