Re: Dishwasher Detergent Dispenser
I had a similar problem with a 7 year old GE. An inspection revealed that the tang in which the spring connected to had broken off. I simply drilled a new hole and reattached the spring, problem solved.
This is a simple mechanism. Remove the inner panel of the door to reveal the mechanicals of the dispenser cup. Inspect the components, if necessary, rotate the dial through a cycle to see the parts move and operate if the problem isn't obvious. You may have to rig it to function again, as I did with mine, though in my case the repair was far more durable than the original design and the dishwasher was working as normal 8 years later when we sold the place and moved.
Another help will be to Google your make and model for a repair manual or at least an exploded view of the unit to help walk you through the repair.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!