Maybe a more indecent way and witout touching the relays is to cut the voltage that feeds the entire control panel, after some minutes. I don't know if this is unhealty for the components, but it gives a more genuine looking failure and you don't have to mess around modifying the PCB to turn off the motor
To disarm "the bomb", the user (you) push a secret switch that disengages the timer before it shuts down the panel
Why you don't post a picture of the washer, and the panel back side?