how can i fix 200 cwe?

both manual pumps and electric pump situated in the water tank accessable/removable throught the switch housing on top of tank.
had a job finding your model so did search very small print top of the thetford page enter c200 cwe and up will come the series yours is in the first lot (1). select yours for the pdf downloads. one exploded view of the toilet.
follow through for your model for pdf downloads that should give you info where the pump is.

uk & europe 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 it doesn't come up)
select customer service (top line)
select products from top line
select bulit in or portable which ever applies.
select user information from list on right.
select repair instructions from list on right
select built in or portable which ever applies.
select select your toilet series model number from right list.
you will now be in the pdf listings for your range of toilets just select those that apply to your toilet and down load them they're free.
as you go through watch for 'ask thetford' on left listings
you may not find what you want and you can send them a message.

for safety reasons which i agree with thetford do not offer repair advice for fridges. refer to service centre

Bob
April 2011