If you have power to the pump, it may just be frozen due to lack of use, corrosion, and the environment it lives in. If you have lights in the panel, you probably have power to the pump. Remember that the level lights and probe have nothing to do with the pump operation. Pull the pump and check to see it you can place a box end wrench on the bottom bolt which holds the macerator blade in place. If you rotate the bolt/shaft, usually it will free up the corrosion. Then squirt a lube(Corrosion Block, T-9, WD-40) into the shaft housing. This has worked for me. Check out the past posts on Groco macerator pumps on this site. I wrote an extensive troubleshooting list for these pumps a year or so ago. I would attach the old post, but I don't know how to do that.
The pump removal isn't nearly as miserable as you might imagine.