Heating element checks good, Hi limit thermostat checks good, thermistor checks good (previous post I indicated bad, but meter was on wrong range.)Dishwasher operates fine, except for heating problem. Inlet temperature 135, but cools down to 107 during wash. I am guessing a bad heater relay on control board. Is there a simple check for this. I am about ready to give in and purchase a new machine. The control board with shipping is almost 25% the cost of a new machine and the machine is showing its age. If it is the relay, can I replace it on the board? Is there something I am missing or that I should check? Please advise.

Note: I replaced pump/motor 3 years ago because of a bad bearing. Dishwasher around 8 years old. If the problem is the control board, on average is there enough useful life in machine to justify replacing an expensive part?