John Deere stx38 - Manual (Page 89)

3/21/97
4 - 5
ELECTRICAL THEORY AND DIAGNOSTIC INFORMATION
READING ELECTRICAL
SCHEMATICS
The schematic is made up of individual circuits laid out
in a sequence of related functions. It is formatted with
all power wires (A) across the top and all ground wires
(B) across the bottom. Current flow is generally from
top to bottom through each circuit and component. All
components are shown in the OFF position. The
diagram does not list connector (C) information unless
needed to avoid confusion. If the connector is shown,
the number next to it is the terminal pin location (D) in
the connector.
Each component is shown by a symbol (E), its name
(F), and an identification code (G). The identification
code contains a device identifying letter (H) and
number (I).
The identifying letter is always the same for a specific
component, but the identifying numbers are numbered
consecutively from upper left to lower right. The
terminal designation (J) is placed directly outside the
symbol next to the connecting wire path. Switch
positions (K) are also placed directly outside the
symbol. The solid line (L) shows the position the switch
is currently in and dash lines (M) represent other switch
positions.
Each circuit is identified at the bottom of the drawing by
a section number (N) and section name (O).
The circuit number (P) and wire color (Q) of the wires
are shown directly next to the wire path.
The same component name and identification code are
used consistently on all diagrams in this section.
Components can be easily cross-referenced.
Link
Fusible
F1
M1
Starting
Motor
B S
M
G1
X1
W1
Shielded
Ground
Battery
Start
K1
Relay
S1 Key
Switch
Off
Run
Start
210
Red
721
Red
Blk
215
Org
F3
Fuse
15 Amp
F2
Fuse
15 Amp
Red
414
Yel/
800
Pink
E2
Spark
Plug
T2
Ignition
Coil T1
Ignition
Coil
X4
Ignition
K2
Seat
S2
Switch
F
Relay
6
X3
710
D
X3
H
805 Pnk/Blk
X3
X2
Pur/
Red
1
X2
X3
E
Seat
Off
Seat
On
Yel/Wht
Yel/
Wht
Blk/Yel Wht
X3
C
X5
Yel/Wht
Wht
B
Wht
105 Blk
Blk
SE1-Power and Cranking Circuit SE2-Ignition and Interlock Circuit SE3-PTO and Interlock
Pur
W2
Engine
E1
Spark
Plug Yel/
Wht
Harness
Wiring
S1
Wht
M
87
85
30
86
L
K
A
D
J
P
Q
N O C
I
H
B
F
E
G