Along with all the excellent advice that these other tech have provided, no one answered the gent's original question. The thermal fuse protects the entire dishwasher circuit from overload. Not just the heater or motor, but everything. From the diagram in the tech sheet, you can see that this fuse is between the incoming line voltage and the door switch. This means it is controlling all power to the dishwasher. Any shorted component can open the fuse.
Generally if you replace both wires etc. that come with the kit you will be OK. More on replacing this TCO here