Hi S.W.S
Your macerator could be jammed. On the end of the pump, there is a rubber or plastic cap (as Tom Hanlon noted....I never had a cap). Pry off the cap and use a flat blade screwdriver to move the shaft of the motor to the right and left to make sure it spins. It will have some resistance because of the rubber flaps inside the pump portion, but you should be able to spin the motor regardless. If it spins, you can then rule out a jam. When doing so, make sure the switch to the pump is off.
On our 2007, the pump gets power from the chassis battery, not from the house batteries as I would have expected. If that is common practice across all PCs, then you'll want to check the fuses in the van portion instead of the house portion. Also, at the pump, pull away the split black slinky-looking wire tubing and make sure the electrical connection above the pump is in good condition, not corroded and not disconnected either. A quick fix would be to disconnect and reconnect, but you would want to clean or replace the connections if badly corroded.
This is the Split Black Slinky Wire Tubing Material I mentioned.

If you determine your pump is dead and needs to be replaced, I just went through that this season detailed
HERE.
Oh, reading the next response from 9X-David.....that too
