Well I'm scratching my head. Saturday I went out and plugged in the block heater as its been -13°C (8.6°F) for a daytime high! It was plugged in for about 1 1/2 hrs. Company showed up so no tractor work that day. I went out and unplugged it. Sunday I again went out plugged it in and nothing. No sizzling, I left it plugged in and like I usually do I went out to the barn an hour later and felt the engine block, it was cold! The tractor will be three years old in March and I have never plugged it in and left it. 1-1.5 hrs is tops for plugging it in. I put my old analogue metre on each end of the plug and it shows resistance so the plug is good. Now I put the meter on the two prongs of the heater and again it sweeps the needle a little bit. I'm not up on this stuff but I remember checking an oven element that way and the burnt out one showed nothing and the new one would move the needle. So here I am! Are they prone to burning out? Thanks for any info.