How to Read Wiring Diagrams
The circuit diagrams by functions show the electrical wiring circuits of vehicles as classified by their functional systems. For those circuits which vary according to vehicle specifications, further division by the functional systems is made.
The harness connectors included in the circuit diagrams are also shown to facilitate comparison with the circuit diagrams.
The fuse specifications and mounting positions are shown in GENERAL, whereas the centralized connectors (fuses and relays centralized at one location) are collectively shown in CENTRALIZED JUNCTION.
1. Indication of Circuits Extending Over Two or More Functional Divisions:
A circuit diagram shows a function-separated circuit from the power supply to the ground. On circuits extending over two or more functional divisions, their destinations are shown so that the mating circuit diagrams can be referred to.
2. Indication of Device Connections:
The circuit diagrams are so made as to show whether the device is attached with wiring or it is designed for direct plug-in.
3. Indication of Connectors in Circuit Diagrams:
A connector in a circuit diagram is shown in a frame and given a connector identification symbol for ease of comparison with connector diagrams and wiring harness diagrams.
4. Indication of Fuses and Centralized Relays:
In the circuit diagrams, fuses are indicated by a waved symbol (~) and the fusible links by a double waved symbol (~).
The fuses in the centralized junction section are given identification numbers (fuse numbers) to allow reference to the centralized junction. The connectors for centralized relays are also given centralized junction identification symbols to allow reference to the centralized junction.
5. Indication of Ground Point:
A centralized ground point is marked with the centralized ground identification symbol in the circuit diagram to allow reference to the wiring harness configuration drawing and ground schematic diagram.
6. Indication of Wires, etc.:
For a wire in a circuit diagram, the wire diameter and wire color are shown. Multiple wires in contact with a frame showing a connector indicate that the wires are connected to the same connector. If there are wires of the same wire color in a connector, their wire color indication symbols in both the circuit diagram and connector diagram are given identification symbols such as *1 and *2 for distinction.
7. Indication of Shielded Cables:
A shielded cable used in an electronic control circuit for example, for prevention of malfunctions that may otherwise be caused by radio interference is indicated by a solid line sandwiched between dashed lines
8. Indication of Specification-dependent Connectors:
Of the harness connectors, the inter-device and -harness connectors which vary in shape or position on different vehicle specifications, such as wiper and radio connectors, are given a specification-dependent connector identification symbol (lower case alphabet) following the serial number of the connector identification symbol, as shown below, to indicate that the connectors are dependent on specifications.
9. Abbreviated Symbols in Circuit Diagrams:
For the abbreviated symbols (abbreviated alphabetical characters) shown in the circuit diagrams.
10. Shapes of Connectors:
In the connector diagram, the connector shapes are indicated by simplified symbols as in the conventional electrical wiring diagrams. For distinction between the male and female connectors.
11. Indication of Spare Terminals of Connector:
In the connector diagram a spare terminal is indicated by - A connector terminal marked X or blackened indicates a guide provided to prevent improper connection.