My new temp guage is giving me fits. It has been installed as per instructions TWICE. It works perfect in air but as soon as it hits the water it goes nuts cycling thru various temps till it settles at 131 drg F. The sensor is turning green suggesting a short but I have sent it back to Lowrance and they replaced the unit but not the sensor. Said it tested good. I called today and they were going to send another sensor. Can anyone shed any lihgt on what I may be dealing with? The unit is wired into a main breaker but that is all and voltage is normal.