I have a 2007 Rockwood Freedom 1640 LTD 8ft, just purchased last week. I seem to be having a little trouble with the sink. No water comes out. I flipped the switch on for the pump, nothing. I also tried to drain old water by turning the knob, on the under seat container. No water came out the bottom of trailer or through (grey water outlet?). Also the pump switch makes a churping sound when it's off, stops when on. Help greatly appreciated.