My new Hunter 33 has a snake river tank indicator for diesel, fresh water and waste water. While I have had no problem with the fresh water and the waste water, the diesel indicator is a big problem. First, the indicator had a reading that the tank was empty when it was full. Then the sensor was changed and at first the reading seemed reasonable(about 8 10ths). Then after taking the boat out, the tank read full(10 10ths). When under way, the indicator is all over the place, but when back at the dock it is full. There was only a wiring harness which attached to the sensor. Is there another ground wire some place which may be loose?