When I press the start button on my Kenmore Elite He5t the machine beeps 3 times and nothing else happens. The other pushbuttons and controls seem to be working. After a few minutes the F71 fault code appears on the digital display. I looked up the fault codes and learned F71 is a communication failure between the user interface and central control unit or a communication failure between the central control unit and the main control board. After further investigation I found a YouTube video that claims the problem is with the motor control board. I used an ohm meter and checked continuity through the ribbon cables from board to board and the connections seemed good. The boards range in price from $200 to $300. I called an appliance service technician who looked at the machine and told me there's no easy way except to replace the boards one at a time but suggested I don't waste my money and just replace the machine.

You have a corroded contact on a wiring harness or where it plugs onto the board. The most common place is a ground wire. All of the mismatched metals in that machine makes the whole thing one giant battery where all of the galvanic activity causes reactions with the most reactive metals. Here is a chart that explains it: https://dl.dropboxusercontent.com/u/...vitySeries.jpg
Look for the most reactive metals attached to less reactive metals, and moisture in the air is enough to corrode the more reactive metal wherever you find the combination. For example, you have stainless steel tied to aluminum, so the aluminum will corrode rapidly unless you attach something made of magnesium as a sacrificial metal anode. The aluminum parts on these machines corrode rapidly unless retrofitted with a piece of magnesium to act as an anode. Here are a couple of manuals that can help: https://dl.dropboxusercontent.com/u/...sher_Elite.pdf
https://dl.dropboxusercontent.com/u/...e%20Manual.pdf
If you are good with a meter you can find the problem in no time. The worst thing you can do is to start replacing parts until you are sure about something. Frequently people will change the control board only to find that the same problem exists with a new board because it's the wiring, not the other components.