Are you sure there is a break in the wiring? it could be jammed or knackered pump, or switch fault.
contact www.thetford-europe.com send email using online form under 'ask thetford'. continue with info below which will also lead you to access the free pdf downloads.
three ways if you found it. 1. Scotch wiring blocks from car shop, or if they have them heat shrink joints, or the small electric terminal blocks.
If repair is going to be in water then ensure you seal it off well.
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, January 2011