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
Slide 3
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.
Slide 4
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.
Slide 5
Power (Positive Voltage) Ground (Negative Voltage)
Slide 6
How many volts?
Slide 7
Understand the Symbols Wiring diagrams contain lots of
information Pay attention to the little details!
Slide 8
Wires cross with NO electrical contact Wires cross with
soldered splice, will have electrical contact
Slide 9
What does this dashed line mean?
Slide 10
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.
Slide 11
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.
Slide 12
How many wires go to this relay? How many wires to the
stoplight module?
Slide 13
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.
Slide 14
A dashed or dotted line can mean there is more than is shown on
the page
Slide 15
Dashed box means the entire Turn/Hazard Switch is not shown
Terminal Pins A11-A17 are shown but not pins A1-A10
Slide 16
A dashed line can indicate there are other wires common to the
circuit, but not shown in the diagram
Slide 17
This splice has five wires in common (parallel circuits) This
splice has other wires, in parallel, that are not shown in this
diagram
Slide 18
The dotted line means there are other circuits sharing this
ground
Slide 19
A dashed line indicates switches are linked
Slide 20
Parking lamp and Headlamp switches are ganged together as
indicated by the dashed line
Slide 21
Slide 22
Slide 23
Other switches inside the headlamp switch operate independently
Parking lamp and Headlamp switches are ganged together as indicated
by the dashed line
Slide 24
Other switches inside the headlamp switch operate independently
Parking lamp and Headlamp switches are ganged together as indicated
by the dashed line
Slide 25
When this coil turns ON this switch will move This switch is
moved by Temperature This switch is moved by Pressure
Slide 26
Slide 27
What does this dotted line mean?
Slide 28
Details on Switches
Slide 29
Draw a continuity block
Slide 30
Wire Details Schematics will often indicate .wire color .wire
gauge size .circuit code
Slide 31
Wire Color Wire Gauge Circuit Code
Slide 32
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 American Wire Gauge
Metric wire size
Slide 33
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
Slide 34
Circuit Code
Slide 35
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!!
