Aft Head problem
You may still have the water intake valve shut. On my 1990 AC the intake valve can only be reached by taking out the lower drawer of the built in cabinet, starboard side of cabin, between berth and head. You have to reach way in to find the actual valve. if you are just turning the valve on the actual head, but don't have the seacock open you'll never get any flush water. Once you do have the intake valve open you may also need to prime the electric pump as you could have an air lock from pumping without water. Lastly, I keep my intake valve closed, and the head valve to dry flush. I keep a gallon of water next to the head to use when wet flushing is necessary. I find this keeps the head smelling better as I am not bringing in biologicals into the bowl or tank. Just my opinion.