Well the way I tested it was to take it back to Advance Auto and tell them it was bad. They gave me another one and I just finished putting it on and still the same, no change. I'm going to get some di-electric grease and make sure the plug to the sending unit is connect really good. The only other option is to change out the sending unit with the one out of the old tank. Its rusted up pretty good, but I know it at least worked. The tests go on...