How do I fix my Indesit WE12 Washing Machine?

Does anyone have the circuit diagram for an Indesit WE12 washing machine or have information that can help me trace a 'door' problem?

On program selection the timer display counts down as normal for a few minutes with nothing else happening (with regards to motor, pump, water intake) then displays 'door'. I tested the door lock mechanism and it iappears ok; neutral is getting from pins 3 to 2 on door closure. I have traced the neutral line from pin 2 of the door latch mechanism and it goes down to the drum heater element then branches off to the motor (and subsequently the pump) and also up to the water intake valves but I cannot detect where it is input to the control PCB. If this wire is not meant to reach the control PCB then how does the 'door' indicator get triggered?

I've had this machine for a few years and it has been used regularly, only giving me trouble (F04 codes etc) when something got trapped in the drain filter. Recently though I've had trouble with the selector switch producing random programs (traced to dodgy contacts on the rotary control switch) and I've been told that error code F-02 has been displayed (motor jammed or tachogenerator detached?) although I have not witnessed this. I don't want to throw the machine out - internally it looks like new - but I am not about to buy expensive parts on an old machine.