Recommend a book on understanding schematics, wiring diagrams, fixing home appliances

Well I suppose you could read a service manual as there is not a lot of stuff available, least officially, so here is a suggestion. If you were to Google Partmaster, then click Curry`s Logik washing machines and type in L612WM13 you will find the beginning of the parts page. If you hit the scroll diagram box you can find the service manual pdf file. This will tell how to service this typical C21st basic washing machine in a rather shaky Chinese translation into English with colour pictures. It is all free ( crickey that is a rarity! ) and there might be a few others pdf files knocking about with some other Chinese brands too if you look out for them. So the question really is if there is a freebee pdf on a 200 quid machine from PRC why isn`t there a free pdf service manual on say a Hotpoint, Indesit, Bosch, Miele etc….draw your own conclusions, I`ve drawn mine!