Virtually all of them fail the same way. One(or more) of the individual LED diodes fail open. They are usually discolored as if they burned. I'm fixing them by

Virtually all of them fail the same way. One(or more) of the individual LED diodes fail open. They are usually discolored as if they burned. I'm fixing them by replacing the diodes that failed (I desoldering them from other lights that failed). I always buy cool white Led lights and all of them use 1W diodes it seems (at least I think they're 1W, there is no writing on them).