Decoding wiring diagram in automobiles

 

Wiring / circuit diagrams are much similar to maps. Roads in a road map lead the user to some predefined destinations. Same is the case for wiring diagram; Wiring/circuit diagram leads the reader to identify the power source, Loads on the circuit and all the intermediate active/passive components provided to control the loads.

3 most important things to remember while trying to interpret wiring diagrams.

  1. Power source
  2. Load
  3. Ground Return.

As mentioned above, an electrical circuit won’t operate without this basic components. Circuit diagram is a blueprint which helps the user to find out missing component from the given three.

 

EL_circuitBasic_circuit_diagram

 

 

 

Next comes controlling loads of the circuit along with safety and auxiliary parts in circuit.  (Relays, fuses, ecus, solenoids, Dash switches, resistors, capacitors etc. )

Initially using analogies could help beginners to learn and reach from moderate to expertise level. But first the user needs to be well aware about different electronics and electrical symbols.

Electrical wiring diagrams are built using some basic symbols for the components used in making the circuit. So a quick check/understanding of this symbols, is must to start decoding the electrical wiring diagrams of automobiles. One such basic list of symbols is given below.

 

circuit-symbols1

Just to begin with ABC’s of reading a circuit diagram, let us begin with one of the simplest circuits – A fog lamp circuit.

 

fog_lights

 

The fog lamp circuit above shows

  1. Battery –   (Power Source)
  2. Relay switch
  3. Fog lamps –  (Load)
  4. Switch
  5. Fuse
  6. Body Ground and wirings.

The image below shows two closed circuit

  • Flip-switch circuit –  Blue colored path
  • Fog lamps circuit. –  Yellow colored path

 

fog coloured

 

Both these circuits are interconnected by a Relay switch in between. When Flip switch is actuated it turns the relay switch on and thus completes the yellow circuit; to switch on the fog lights. Relay acts as an electronic switch for the circuit.

6 thoughts on “Decoding wiring diagram in automobiles”

  1. Thanks for your info. If installing a dimmer switch, you say the wire from the switch to the lights will be white. Is this a third wire or does it replace the black wire?

    Thanks.

  2. I?m impressed, I must say. Really rarely do I encounter a blog that?s both educative and entertaining, and let me tell you, you have hit the nail on the head. Your idea is outstanding; the issue is something that not enough people are speaking intelligently about. I am very happy that I stumbled across this in my search for something relating to this.

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