On our '02 Georgetown, there are heater elements on both the black and grey tanks but not on the potable water tank. According to the supplier documentation, they are 12V DC elements and draw about 7 amps for each tank.
When the Arctic Pack (spelled by GT as "Artic!) the non-adjustable, built-in thermostats turn the elements on when they sense the contents are dropping below 40F and off again when the contents get to 65F. Who the hell needs to heat up the poop in the black tank to 65 degrees?! With that level of contamination, the contents probably wouldn't freeze until about 25F anyway.
Since nothing's adjustable and the whole system looks like a riduclous waste of money on the part of the original purchasers (particularly for the Pacific Northwest climate), I don't plan to ever switch it on.
Frank and Eileen
No longer RVers or FR owners