The following should help as there are many types some with pumps direct some with electronic valves these work from the main water tank pump sending water into toilet flush via a none return valve.
If the C2 bench type facing the toilet the flush /blade opening button is on the left side on the right is the sunken toilet roll holder which pulls out but you may need to gently prise it out working around it, smear vaselene around rim on replacing it make for easy removal, underneath this is the pump in a cage held down by ONE cross head screw. undo that lift pump out You pull off the flush tube and cut the cable but you may find the problem is the impeller blade on the base of the pump is stuck turn it gently a few times with small screwdriver until it feels fairly free then try it out. Don't run dry drop it in water tank or you ruin the pump. If you have to replace the as above don't pull the old cable out cut and splice in the new pump using heat shrink joints on the wires. One of the wires has a secondary tracer colour to Identify it's positive + so has the new pump connect the two wires with tracers together don't mix one trace with one plain you'll most like burn out the pump. If It's not the bench type the get on to thetford on page 3 'ask thetford'.
SEE TIP BELOW.
UK www.thetford-europe.com
Australia www.thetford.com.au (Even get request from Australian campers)
Australia site has stockist list.
HOME PAGE SELECT ENGLISH {if in Australia forget this selection)
NEXT PAGE SELECT CUSTOMER SERVICE (top line)
NEXT PAGE SELECT USER INFORMATION (left of pic) also 'Ask thetford' is on this page.
NEXT PAGE SELECT REPAIR INSTRUCTIONS (left of pic)
NEXT PAGE SELECT BUILT IN TOILETS [top right of pic]
NEXT PAGE SELECT This is where you select your toilet range. Search alll if unsure of type/range
NEXT PAGE PDF Files You should be in the pdf folder list on your Thetford toilet. Start downloading.
To direct link to the Thetford download site type in the following
www.thetford.eu/web/show/id=51498/langid=42
Don't bother for Thetford fridges they tell you for safety reason to take it to a service centre
TIP: When replacing pump
Never try replacing the pump cable back to micro switch unit unless it's really necessary. To do so you'll have to take the whole unit out. Just cut the old wire and splice to the new pump wire using heat shrink sleaves obtainable in some auto shops. Watch the wire with thin trace colour [eg: white with black thin tracer colour] no matter if the wires are different colour make sure that you joint the wires with tracer colour on the old pump wire to the wire with a tracer on the new pump,then obviously join the two plain ones together.
Hope it's all clear.
Bob, January 2010