Dishwasher still will not heat water or dry

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?

Problem solved. Replaced control board assembly containing burned and defective heater relay.