[Dapper Dan]

My black tank does not empty when I open the pull handle. Does anyone have the waste plbg diagram for 2005? I think the shower, bath sink drains into the black water tank. Kitchen sink drains into Grey water tank. I've run a snake 15' into the black water tank but nothing came out and no debris was noted. The sensor read 2/3 full and I've eeyeballed the tank and the waste level is above the sensor. There is screw clamps that attach the black and grey pipes too the tanks I think but I haven't dissconnected them. Help!!!!