Symbols in car wiring diagrams:
Electrical components:
* B – Battery
* C – Capacitor
* D – Diode
* F – Fuse
* G – Generator
* H – Headlight
* L – Coil
* M – Engine
*P – Relay
* R – Resistor
*S – Switch
* T – Transistor
* U – Control unit
* V – Voltmeter
* W – Speaker
Wire types:
* Black: Ground (ground)
*Brown: Positive (+) 12V
*Red: Positive (+) 12V after ignition switch
*Yellow: Positive (+) 12V from generator
* Green: Signal wires (eg from sensors)
* Blue: Control wires (eg from switches)
*Orange: Lighting wires (eg for lamps)
* Purple: Data bus wires (eg CAN bus)
Other designations:
* ECU: Electronic control unit
*ECM: Engine Control Module
* BCM: Body Control Module
* ABS: Anti-lock braking system
* SRS: Safety Restraint System (Airbag)
Designation principles:
* Wires are usually marked with lines indicating the type of wire (for example, a brown line for a 12V power wire).
*Components are identified by symbols or letters in circles (for example, a circle with a “B” for battery).
* Connections are indicated by the points where lines intersect.
* Earth (mass) is usually represented by a grounding dot or symbol.
*Wire numbers are usually indicated next to the lines.