This happened to me last week. I checked everything I could and found nothing wrong. I had power to the switch and through the switch. I came in the house to query contour.org and, miraculously, when I went back out a few hours later, everything worked well. The temperature had dropped about fifteen degrees and my "black" SVT was no longer in the sun. I suspect there is a thermal breaker that reset itself after cooling down. I hope your luck goes as well!
