Reading appliance wiring diagrams and tech sheets

A schematic (ladder) shows how current flows: the supply rails run along the top or sides, and each rung is one path through switches to a load. A wiring (pictorial) diagram shows where the wires physically run, with connector and pin numbers. Use the schematic to understand logic, the pictorial to find the wire.

On a 120 V appliance, L1 is the hot conductor and N is neutral; loads sit between them. On a 120/240 V appliance (electric dryer, range), the 240 V heater sits between L1 and L2, while 120 V parts (motor, timer, light, control) run from one leg to neutral.

Switches are drawn in their resting (de-energized, door-open or cold) state unless the sheet says otherwise. Thermostats and thermal fuses are drawn closed when cold; door switches are usually drawn open.

Connectors are labelled by plug and pin (for example a board connector ID plus pin number). Wire colors are abbreviated (BK, WH, RD, BU, OR, etc.); tracer stripes are shown as a second color.

A strip circuit is a way to isolate one function: follow only the path that powers the failing load from L1 to N (or L2), list every switch, connector and fuse in that path, and test each in order. The open part is somewhere between the last point with voltage and the first point without it.