Probably because you don't have a watt meter. I do and that is the only way I know how much power the heater uses. It is NOT in the service manuals, both DVD and printed. You are welcome...
I really like the desulphator, but I would NOT buy anything from NORTHERN. I don' t trust those guys. There are other people who sell them. I got mine from Chubbydutchman on eBay. Do a search for him (seller).
The block heater in my 2007 F350 draws 6.2 amps. I've checked it a few different times and it's always 6.2. This is with a true RMS fluke digital ammeter. Hope this is what you're looking for.
Jeff
That is about right, Bat. 120v X 6.2A = 744 watts. My block heater was measured , by me, at 925 watts using a watt meter. The heater is rated at 1000 watts. Give or take, it is with in a reasonable range. If you are still having starting problems I would consider taking it in and having a new heater installed.
guess the bottom line is i should go find me a 'watt meter' and do my own test so i would know for sure....perhaps it is faulty - as the factory cord went out a few years ago...