Whirlpool Duet Washer, no Operation

[TechnicianBrian]

Model #WFW9400SU01, This new front load washer arrived at the customers home right out of the box, but once connected to the plumbing and plugged into the wall outlet, the display remained blank and the buttons on the user interface didn't function. Discouraging for the customer indeed, and this isn't the first time I have witnessed this particular failure, but I do know how to fix it.



Lines of Communication
The problem with this type of failure is simply the lack of diagnostic information that we as technicians are given by the manufacturers. In this washer, there are three electronic control boards that contain the control, display, and user interface functions, and all three of them are connected to each other via communication lines. These lines of communication allow for the boards to 'speak' to each other, but because we are not able to 'speak' their language, it is difficult to determine which board is causing the problem because it is either not speaking or not listening to the conversation.


Without this information, we as technicians either take educated guesses as to which board to replace, or worse (for the manufacturer), we just order all the boards in case we need them. Not the most effective way to troubleshoot, but without the benefit of detailed information, that is what we are left with.

Seeking Answers
Now as I said before, this isn't the first time I have seen this problem, and me being the curious type, like to get out my meter and try and find the information that will allow for a better diagnosis of the problem. What I have learned so far is to first verify voltage to the CCU board. If you don't have power to the board, you are dealing with a different problem. Once voltage to the board is verified, check the output from the CCU board to the UID connector of the right display board for a 5vdc and 10vdc reading between the two outside wires. No voltage indicates a failure of the CCU board and it needs to be replaced. If you read power to the right display board, but still no operation, then one of the display boards has failed and they both need to be replaced.

The Fix
On this washer, I was reading 6.3vdc on the UID connector which indicated the CCU board is functioning and is not causing the interface issues. This leaves me with one of the display boards causing the problem and since I cannot tell which one is the culprit, they both get replaced (per Whirlpool BTW). After replacing both the middle , and the right display boards, this washer was finally able to be used to wash clothes.

[JWWebster]

Dang electronics. 3 boards? You could not pay me to own a whirlpool duet washer with all the problems I have read about and I have never even seen one.