John Deere stx38 - Manual (Page 88)

4 - 4
3/21/97
THEORY AND DIAGNOSTIC INFORMATION ELECTRICAL
THEORY AND DIAGNOSTIC
INFORMATION
THEORY OF OPERATION
INFORMATION
The theory of operation stories divide the electrical
system into individual circuits by function. Each circuit
is isolated from the main wiring schematic and only
shows the components that are used in it. The story
contains information on function, operating conditions,
and theory of operation. The circuit schematics are
drawn with the components in the operating position,
with the power, or battery positive, into them across the
top and the ground, or battery negative, across the
bottom.
DIAGNOSTIC INFORMATION
The diagnostic procedures is used to test the complete
circuit regardless of the problem or complaint. Select a
symptom or system from the quick check or
troubleshooting chart and follow the test procedures
under that heading.
The diagnostic procedure lists:
• Test conditions
• Test sequence
• Test location
• Normal reading
• Check or test to perform if reading is not normal
When performing the test or check, be sure to set your
machine up to the test conditions listed and follow the
sequence carefully. The middle “NORMAL” column
gives the reading or condition that should be obtained
when performing the test or check. If the results of the
test or check are not normal, perform the test, check, or
adjustment listed in the third “IF NOT NORMAL”
column to repair the malfunction. The detailed tests or
adjustments referred to in the “IF NOT NORMAL”
column are located at the end of that group. The
system diagram that accompanies each test procedure
is drawn to resemble machine components. The key
number on the art matches the number in the “TEST
LOCATION” column and the leader line points to the
exact point the test is to be made.
WIRE COLOR ABBREVIATION
CHART
Blk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Black
Blu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Blue
Brn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Brown
Grn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Green
Gry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gray
Org . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Orange
Pnk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Pink
Pur . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Purple
Red. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Red
Tan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tan
Wht. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .White
Yel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yellow
Blk/Wht. . . . . . . . . . . . . . . . . . . . . . . . . .Black/White
Blu/Wht. . . . . . . . . . . . . . . . . . . . . . . . . . Blue/White
Brn/Wht . . . . . . . . . . . . . . . . . . . . . . . . Brown/White
Brn/Yel . . . . . . . . . . . . . . . . . . . . . . . . Brown/Yellow
Dk Blu. . . . . . . . . . . . . . . . . . . . . . . . . . . . Dark Blue
Dk Brn/Lt Grn . . . . . . . . . . Dark Brown/Light Green
Dk Brn/Red. . . . . . . . . . . . . . . . . . Dark Brown/Red
Dk Brn/Yel . . . . . . . . . . . . . . . . . Dark Brown/Yellow
Dk Grn . . . . . . . . . . . . . . . . . . . . . . . . . Dark Green
Lt Blue . . . . . . . . . . . . . . . . . . . . . . . . . . . Light Blue
Lt Grn . . . . . . . . . . . . . . . . . . . . . . . . . . Light Green
Lt Org . . . . . . . . . . . . . . . . . . . . . . . . . . Light Orange
Org/Wht . . . . . . . . . . . . . . . . . . . . . . . Orange/White
Pnk/Blk . . . . . . . . . . . . . . . . . . . . . . . . . . Pink/Black
Pur/Wht . . . . . . . . . . . . . . . . . . . . . . . . Purple/White
Red/Blk. . . . . . . . . . . . . . . . . . . . . . . . . . . Red/Black
Red/Wht . . . . . . . . . . . . . . . . . . . . . . . . . . Red/White
Wht/Blk. . . . . . . . . . . . . . . . . . . . . . . . . .White/Black
Wht/Red . . . . . . . . . . . . . . . . . . . . . . . . . . White/Red
Yel/Blk . . . . . . . . . . . . . . . . . . . . . . . . . Yellow/Black
Yel/Red . . . . . . . . . . . . . . . . . . . . . . . . . Yellow/Red
Yel/Wht. . . . . . . . . . . . . . . . . . . . . . . . . Yellow/White