A typical electrical circuit consists of switches, relays, motors, fuses, calibrated fuse wires, thermal fuses interconnected by wires.
Before starting troubleshooting, read the relevant circuit: if several components of the circuit do not work, the fault is most likely in a fuse or poor contact with "weight".
Basic tools needed for troubleshooting wiring: voltmeter, test lamp, conductivity tester (lamp with independent energy source), ohmmeter.
In general, all faults in the electrical circuit are reduced to the absence of contact where it should be, and the presence of contact where it should not be.