got my truck at the start of last summer, just went outside to find the plug in......cant find it? A buddy of mine said to look for a black bag or something tucked up around the engine on the passenger side?
imo, you dont really need it unless you are seeing negative degrees...
also if you plug it in at night, I'd put it on a timer so it only starts a couple hours before you wanna use it.
Oh it doesnt hurt anything that im aware of...just costly to keep it plugged in. I've started both my LLY and LBZ in -5 or -7F weather w/o any issues, didnt even have to cycle the plugs more than once!