I have a 2003 Key West Bay Reef. My fuel gauge registers empty all the time. I checked the voltage on the hot side of gauge which is the purple wire. There is 12.5v there. On the sender side of the gage there is 3.5v. If I remove the pink sending wire from the gauge it makes no difference. I still have 3.5v on the sender post of the gauge. What should I be reading. Thanks