Wow, was not expecting 'you probably did something wrong'. For the record, I tested outdoors, with the knob turned to lo then hi heat, at 26 degrees. Then I tested at another connection, where it failed, and upon removing it, broke a prong off my extension cord because the receptacle holes are too tight. It is a brilliant idea and I was glad to find it. I'm not accusing the product line of being bad, I'm saying I got a bad one and there are bad ones out there. Perhaps whoever was in charge of quality control retired and was not replaced, or was replaced by an incompetent.