The block heater cord on my old chevy was tied around through the grill.
Wife backed out with it still pluged in.
Do you know how many pieces a chevy grill explodes into when its 30 below?
Lots!

 

Ever forget to unplug your truck!....Nope never, been plugging in for years, guess it's just second nature for us. Did have a hand install a new heater on a loader once and when he ran the cord, he zip tied it to the hyd/ram. It was plugged in all night, so when I came in I unplugged it, got on and started it, let it warm up a bit, went and did what I needed to do. When I got back to the shop the mech. is all bitchy and waving this piece of cord at me. He's accusing me of not unplugging the cord. He walks over to the loader to see if it could be spliced back on, then we see what he had secured the cord too, he had it tied to the lift ram and when I raised the bucket it ripped the cord in half.

To tell if your heater is plugged in...bend over and listen by your r/f tire, you should be able to hear it percolating. I also have this Fluke 68
Infrared Thermometer. I just point it at area around heater to see if temps are rising. http://www.testequipmentdepot.com/fl...ometers/68.htm
I have it for work, but have used it to test how well my heat pads perform in extreme cold.

Here's a couple smaller ones http://www.maxtool.com/index/Digital...ermometers.asp

I might get the MTPRO myself just because of lower temp range.