How can I fix my NEFF S4133 dishwasher?

We have been given an old Neff S4133 dishwasher which kind of works - the water heats, the arm can rotate, it pumps out, but the mechnical programme knob does not click through the sequence, so it for example takes in water, heats it, but doesn't go into the wash programme. I think it is only a sticky switch. How can I lubricate it? As it is an old second hand machine, I am reluctant to spend money on taking it to a repair shop - plus it is incredibly heavy and difficult to move! Hope you can help. Thanks.