Thats the way it is wired and with it being on the same circuit as the glow plug controller it kills the power to the gp's when it blows.It had a 30 amp fuse in it.Even when I unplug the ip and the feul filter heater it still blows the fuse as long as that sensor is plugged in.I dont think the sensor is grounded but I need to recheck that.Its raining pretty good here so it may take me a couple of days to get to it.That and working too.