You can find an online manual on their website. I don't know your model number to help with the problem but can point you in the right direction. Please see below website.
www.smeguk.com
click on "uk" on the right then "after sales"
then below the phone numbers in the middle section click on the bit that says "User Manuals" which brings up a new page.
then click on "Dishwashers" from the menu on the left
then find your model number
Model numbers can usually be found on appliances on a sticker either on the side or the back so you might need to pull it out.
Take a note of the service phone number they may be able to help further.
Donna Campbell, July 2009