I am in NO way an electrical expert............however
if the light in the switch for the arctic package were wired in "series" as opposed to "parallel"......this is where the experts can explain the difference in a wiring schematic.........if the light were burnt out, the heating package would NOT work because there would be an "open" in the complete electrical circuit. Conversely, if there were a malfunction or "open" in the actual heating pad of the arctic package, the light in the switch would not light up when you turned it on. No light anytime, would indicate to the user there is a problem. You figure it out where now.
Personally, I think this is always the better way to wire circuits when there are indicator lights in a circuit. From what you're describing, you've somehow determined the heating pads are working, without the switch light being on. Guess you really don't need a light in the switch afterall, just look at the physical position of the switch.....is it "on" or "off"?