Have you cured it? f not then test fuse with car 12volt screwdriver tester unless you can see it's blown....thetford list them as 3amp.
If it's not the fuse test the current is getting to the pump by turning on a 12volt light you can see and pressing the flush switch if the light dims then current is getting to the pump but the pump is either jammed or knackered
I'll take you through repairs/replacements I've done two c2's.that had jammed pumps
robertwhiting76@hotmail.com
Bob
September 2008