How to Troubleshoot & Replace Whirlpool AP4010055 / 12001725 Control Board

After carefully reading the MAH3000 service manual and consulting the wiring diagram I checked the rinse side of pressure valve while filling the tub with water. The contact closed when the tub filled to the rinse level of 4 to 5 inches deep - OK. Then I monitored the P1 connector pin 1 (input from the pressure switch) on the control board and found that it is energized and the control board should be commanding water valve on. At this point I concluded that the control board was at fault and replaced it. The Washer still did not fill on the rinse cycles. At this point I had only updated the control board from firmware level HNP101 to HNP106. At his point I checked the Timer carefully, pin 8T did not close for the rinse cycle as the CAM Information diagram shows. Replacing the timer fixed this problem. The service manual does not explain the function of input 1A Conn P7 pin 8. The trouble shooting section of the service manual does not cover this failure. 

Once it was determined the parts I needed to solve the problem I ordered them. They arrived as promised. The hardest and what took the longest was getting the old wax motor out. Once replaced the board was easy. Plugged machine back in and ran a test load. Works just like before. 

Did a couple of Google searches and found one that matched my situation. The video showed that location R13 on the main processing was burned. This was an indicator that the door lock was bad. So, a ordered a new door lock and main processing board.