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.
If I wanted to test the blower
fuse I would not be surprised
to find other fuses in this box
The entire Blower Motor Switch is
shown in this schematic
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 indicates
switches 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
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
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
Which is the larger wire?
AWG
4
12
14
16
18
20
???????
American
Wire Gauge
4!
19.0
3.0
2.0
1.0
0.8
0.5
??????
19.0!
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!!