Kennmore Dishwasher, apparently made by Whirlpool, 665.17034402

Cycles do not complete: they pause with water in bottom below heater coil, leaving start button endlessly flashing.

"Heated Dry>Normal>Heated Dry>Normal" diagnostic resets unit, but problem repeats.

What tests should I do before replacing control panel?

If needed, where can I purchase the correct control panel for this unit?

This unit was installed in 2005 --> 7 years ago.
How many miles does it have left in it? Is it worth repairing?

Thanks in advance -- I appreciate your time, knowledge and experience.
-Ed