On some newer models, you can push any 3 buttons in the following sequence: 1-2-3-1-2-3-1-2-3, with no more than a second between each button push. That will put the dishwasher in diagnostic mode. This is the case for our Whirlpool dishwasher bought in late 2014, which doesn't have dedicated 'heat dry' and 'normal' buttons. Rather, it has fewer buttons, each of which can be toggled through several states which include 'heat dry' and 'normal'. So the traditional method of pushing just those 2 buttons in sequence repeatedly didn't work for me. I only learned this new method by pulling off the plastic panel next to the floor, and finding instructions for repair technicians stored there in a plastic bag. It might be worth looking for such instructions stored under your model.