Wiring Diagrams Wiring Diagrams Wiring Diagrams
Wiring Diagrams Wiring Diagrams Wiring Diagrams
Wiring Diagrams Wiring Diagrams Wiring Diagrams
Wiring Diagrams Wiring Diagrams Wiring Diagrams
Wiring Diagrams
Schematics
Wiring Diagrams or Schematics use a symbolic language
Understand the symbols and the diagrams will talk to you
What it can tell you is how and where to test the system
Listen to the Diagram!
Wiring Diagrams explain how a circuit works
All electrical circuits need Power (positive voltage), conductors, controls, loads.
To understand how a circuit works you must trace powerflow through the conductors, controls, and loads.
Power at the top!
Positive voltage is often called power.
Positive voltage usually originates in the top and left side of the diagram.
Ground is usually found at the bottom and right side of the diagram.
Power(Positive Voltage)
Ground(Negative Voltage)
How many volts?
How many volts?
How many volts?
Understand the Symbols
Wiring diagrams contain lots of information
Pay attention to the little details!
Wires cross with NO electrical contact
Wires cross with soldered splice, will have electrical contact
What does this dashed line mean?
A dashed (or dotted) line can indicate there are other devices not shown in this picture
To keep the diagram simple, the other electrical components are not shown
The schematic says a 40 amp fuse is in the fuse/relay box. The fuse should always have power to it. The dotted line means there are other items in this fuse/relay box.
The Engine Compartment Fuse/Relay Box has other wires, fuses etc.
The entire Blower Motor Switch is shown in this schematic
If I wanted to test the blower fuse I would not be surprised to find other fuses in this box
To find this switch I would look for a switch with four wires.
How many wires go to this relay?
How many wires to the stoplight module?
More Dashed Lines
A dashed or dotted line can mean there is more than is shown on the page…..
…..Or there are other wires hooked to the circuit, but not shown in the diagram
…..Or what controls a switch.
A dashed or dotted line can mean there is more than is shown on the page
Dashed box means the entire Turn/Hazard Switch is not shown
Terminal Pins A11-A17 are shown but not pins A1-A10
A dashed line can indicate there are other wires common to the circuit, but not shown in the diagram
This splice has five wires in common
(parallel circuits)
This splice has other wires, in parallel, that are not shown in this diagram
The dotted line means there are other circuits sharing this ground
A dashed line indicatesswitches are linked
Parking lamp and Headlamp switches are “ganged” together as indicated by the dashed line
Parking lamp and Headlamp switches are “ganged” together as indicated by the dashed line
Parking lamp and Headlamp switches are “ganged” together as indicated by the dashed line
Other switches inside the headlamp switch operate independently
Parking lamp and Headlamp switches are “ganged” together as indicated by the dashed line
Other switches inside the headlamp switch operate independently
Parking lamp and Headlamp switches are “ganged” together as indicated by the dashed line
When this coil turns ON…
…this switch will move
This switch is moved by Temperature
This switch is moved by Pressure
What does this dotted line mean?
What does this dotted line mean?
What does this dotted line mean?
What does this dotted line mean?
What does this dotted line mean?
What does this dotted line mean?
What does this dotted line mean?
Details on Switches
Draw a continuity block
Wire Details
Schematics will often indicate…
….wire color
….wire gauge size
….circuit code
Wire Color
Wire Gauge
Circuit Code
Wire Gauge
4 12 14 16 18 20
???????
4!
19.0 3.0 2.0 1.0 0.8 0.5 ??????
19.0!
Which is the larger wire?AWG
AmericanWire Gauge
Metric wire size
Not all schematics are the same
Some diagrams will leave out detail
Color Codes change ….
….B could be Blue
….OR….
….B could be Black
The order of wire coding can also change
Circuit Code
Not all schematics are the same
When you see a new symbol look it up!
The better you are at reading diagrams... ...the more mental power you will have… …available to diagnose and fix the problem!!