Reading Wiring Diagrams - Symbols (continued)
Z-GI-9spec tableSymbols (left column)
Horn
MeaningGenerates sound when current flows.
Speaker
Meaning
Heater
MeaningGenerates heat when current flows.
Speed sensor
MeaningMovement of magnet in speedometer set turns contact within sensor on and off.
Ignition switch (Normally open NO)
MeaningTurning ignition key operates switch contacts to complete various circuits. Positions: ST, OFF, ON, ACC.
Relay (1) (Normally open NO)
MeaningCurrent flowing through coil produces electromagnetic force causing contact to open or close.
Relay (2) (Normally closed NC)
MeaningCurrent flowing through coil produces electromagnetic force causing contact to open or close.
Sensor (variable)
MeaningResistor whose resistance changes with operation of other components.
Sensor (thermistor)
MeaningResistor whose resistance changes with temperature.
Capacitor
MeaningComponent that temporarily stores electrical charge.
Solenoid
MeaningCurrent flowing through coil generates electromagnetic force to operate plungers, etc.
Symbols (right column)
Switch (1) Normally open (NO)
MeaningAllows or breaks current flow by opening and closing circuits.
Switch (2) Normally closed (NC)
MeaningAllows or breaks current flow by opening and closing circuits.
Harness (Not connected)
MeaningUnconnected intersecting harness.
Harness (Connected)
MeaningConnected intersecting harness.
Diode
MeaningKnown as a semiconductor rectifier, diode allows current flow in one direction only. Cathode (K) -> Anode (A). Flow of electric current: K -> A, K -> A, K -> A.
Light emitting diode (LED)
MeaningDiode that lights when current flows. Unlike ordinary light bulbs, diode does not generate heat when lit. Cathode (K) -> Anode (A). Flow of electric current: Cathode (K) -> Anode (A).
Reference (zener) diode
MeaningAllows current to flow in one direction up to a certain voltage, allows current to flow in other direction once that voltage is exceeded.
Relay contact behavior
Normally open relay (NO)
OpenNo flow
ClosedClosed
Normally closed relay (NC)
OpenFlow
ClosedNo flow