Wire Number
Wire Color
101
RD
102
Wire Description Wire Number
Wire Color
Bat (+)
447
PK
Fuel Level Gauge
BU
Hd Lmp
450
YL
Tach Sender (+)
103
YL
Aux Ckt
483
BR
Brake Fluid Level
105
BR
Key SW
109
OR
Alt Output (+) Term.
500
BR
Wiper - Front (Park)
112
PU
Main Power Rly Output
501
GN
Wiper - Front (Low)
113
OR
Opr Mon Panel Switched
502
OR
Wiper - Front (HI)
116
BR
Aux Ckt
503
BR
Wiper - Rear (Park)
118
GY
Aux Ckt
504
YL
Wiper - Rear (Low)
119
PK
Aux Ckt
505
BU
Wiper - Rear (HI)
120
YL
Aux Ckt
513
OR
A/C Compressor/Refrigerant Pressure SW
121
YL
Bckp Alarm to Lamp
515
GY
Blower Motor (HI)
122
BU
Aux Ckt
516
GN
Blower Motor (Medium)
123
WH
Aux Ckt
517
BU
Blower Motor (Low)
124
GN
A/C
520
WH
Opr A/C Sw to Thermostat/Fuse
126
PK
XMSN Ctrl
521
YL
A/C Sw to Refrigerant Sw
128
PK
Aux Ckt
522
WH
A/C Clutch to Thermostat Sw
143
BR
Aux Ckt
536
WH
Hazard Sw to Turn Sw
157
YL
Aux Ckt
552
WH
Four Wheel Drive Sol
161
PK
Aux Ckt
568
GN
Warning Buzzer to Diodes
194
GN
Aux Ckt
Description Power Distribution Circuits
Code Flashed
11 12 31 32 33 34 35 36
CID - FMI No ACTIVE Faults No INACTIVE Faults 641 - 05
642 - 05 643 - 05 644 - 05 645 - 05 646 - 05
37
683 - 05
41 42 43 44 45 46
641 - 06 642 - 06 643 - 06 644 - 06 645 - 06 646 - 06
47
683 - 06
51 52 53 54 55 56
641 - 03 642 - 03 643 - 03 644 - 03 645 - 03 646 - 03
57
683 - 03
69 71 72 73
668 - 02 168 - 00 168 - 01 650 - 02
Description
9W-1520
Start Aid
37.8 ± 2.8°C 100 ± 5°F
26.7°C MIN (80°F MIN)
Normally Closed
9D-6888
A/C Low Pressure
234 kPa MAX (34 psi MAX)
152 kPa MIN (22 psi MIN)
Normally Open
Resistor And Solenoid Specifications
Component
Part No.
Resistance (Ohms)¹
Resistor - A/C Blower
7T-3828
Overall - 1.0 ± .1; Tap - .5 ± .05
202
BK
XMSN Ctrl
605
YL
Turn Lamp - Left
Resistor - Key Switch
8C-4110
22 ± 1.1
Turn Lamp - Right
Solenoid - A/C Clutch
7T-7825
3.5 ± 0.15
3E-8620
32.1
6T-6885
8.9 ± 0.3
BK
XMSN Ctrl ldent Code 0
606
GY
277
BK
XMSN Ctrl ldent Code 1
608
GN
Flood Lamp - Rear
Solenoid - Bucket Positioner
278
BK
XMSN Ctrl ldent Code 2
610
OR
Head Lamp Basic
Solenoid - Front Drive
278
BK
XMSN Ctrl ldent Code 3
614
PU
Park/Tail/Dash Lamp
Solenoid - Start Aid
3T-9493
1.5
280
BK
XMSN Ctrl ldent Code 4
617
BR
Tail/Position Lamp - Left (Road Pkg)/Width
Relay - Start
3E-9362
90 ± 9
281
BK
XMSN Ctrl ldent Code 5
618
YL
Tail/Position Lamp - Right (Road Pkg)/Width
¹ At room temperature.
620
WH
Flood Lamp - Front
BU
Starter No. 1 Sol
630
GY
Flood Lamp Rear (Attach)
303
BR
Key Sw Acc Position
639
WH
Left Hand Stop/Tail Lamp
304
WH
Starter Rly No. 1 Output
640
GN
Right Hand Stop/Tail Lamp
306
GN
Starter Rly Coil to Neut Start Sw or Key Sw
307
OR
Key Sw to Neut Start Sw
720
PU
XMSN Brake Sw
308
YL
Main Power Rly Coil
751
GN
XMSN Shift Sol No. 1 or 3
309
GY
Alt Regulator Term.
752
YL
XMSN Shift Sol No. 2
310
PU
Start Aid Sw to Start Aid Sol
754
BU
XMSN Shift Sol No. 3 or 1
311
WH
Start Aid Sol to Temp Sw
755
OR
XMSN Shift Sol No. 4 or 5
321
BR
Bckp Alarm Lamp Travel Alarm
762
YL
Bucket Positioner Sol Sw
322
GY
Warning Horn (Forward)
900
PU
XMSN Shift Sol No. 5 or 4
326
PU
Key Sw “C” Term.
901
WH
XMSN Shift Sol No. 6
944
OR
Data Link + (CAT) Data Link - (CAT)
Opr Mon Oil Press. (Lo Setting)
945
BR
406
PU
Opr Mon Coolant Temp
958
YL
Relay Logic
409
OR
Opr Mon Neut
965
WH
Trans Sol 1 Sw to Gnd (Fwd Hi:CST, Rev:LRT)
415
GN
Opr Mon Test Sw
966
GY
Trans Sol 3 Sw to Gnd (Fwd Lo:CST, 4th:LRT)
415
GN
Opr Mon Test Sw
968
BR
Trans Sol 2 Sw to Gnd (Rev:CST, Fwd:LRT)
417
GY
Primary Ster SW
969
YL
Trans Sol 3 Sw to B+ :CST, for LRT Sol 2
419
YL
Opr Mon Parking Brake
970
GN
Trans Sol 4 Sw to Gnd (Spdl:CST, 3rd:LRT)
441
OR
Eng Coolant Temp Gauge
971
YL
Trans Sol 5 Sw to Gnd
443
YL
Power Train Temp Gauge
972
BU
Trans Sol 6 Sw to Gnd (Spd3:CST, 1 st:LRT)
447
PK
Fuel Level Gauge
975
WH
Cst Autoshift - Sol Return
450
YL
Tach Sender (+)
C920
GY
Action Lamp - Control
483
BR
Brake Fluid Level
E999
GN
Reverse Parity (Sol 1 to B+)
Component
Alarm - Backup
A-9
Component Location Component
Schematic Location
Machine Location
D-7
A
1
Resistor - Blower (Heater)
Alarm - Park Brake
C-6
A
Resistor - Key Start
Alternator
B-2
2
Sender - Converter
B-2
14
Battery
A-3
3
Sender - Coolant
C-1
15
Beacon - Fixed
E-9
4
Sender - Fuel
F-4
16
Beacon - Fixed
F-9
4
Solenoid - A/C Clutch
D-1
17
D-4
F-9
4
Solenoid - Bucket Positioner
A-4
8
Breaker - Acc Relay
B-8
A
Solenoid - Engine Shutdown
E-2
18
Control - Shift
D-5
5
Solenoid - Front Drive
C-3
19
Control - Transmission
A-5
6
Solenoid - No. 1 (Reverse)
B-2
14
Diode Block As
E-5
B
Solenoid - No. 2 (Forward)
C-2
14
Flasher
C-7
A
Solenoid - No. 3 (Fourth Gear)
C-2
14
Fuses
F-5
A
Solenoid - No. 4 (First Gear)
C-2
14
Fuses
C-9, D-9
A
Solenoid - No. 5 (Second Gear)
C-2
14
D-8
A
Solenoid - No. 6 (Third Gear)
C-2
14
Gauge - Coolant Temp
E-8
A
Solenoid - Start Aid
A-2
7
Gauge - Fuel
D-9
A
Starter
A-2
20
Gauge - Voltmeter
D-8
A
Switch - Beacon
E-7
A
Horn - Forward
A-2
7
Switch - Blower
F-5
9
Lamp - Action
A-7
8
Switch - Brake
C-2
21
Lamp - Brake Fluid
D-3
B
Switch - Brake (2)
E-4
22
Not Applicable
Lamp - Coolant Temp
E-3
B
Switch - Coolant
C-2
15
Lamp - Engine Oil Pressure
E-3
B
Switch - Engine Oil
C-2
23
Lamp - Front Drive
D-3
B
Switch - Flood Lamp (Front)
E-7
A
Lamp - Left Turn Indicator
E-3
B
Switch - Flood Lamp (Rear)
E-7
A
Lamp - Park Brake
E-3
B
Switch - Flood Lamp (Rear)
E-9
A
Lamp - Primary Steer
D-3
B
Switch - Forward Horn
D-3
B
Lamp - Right Turn Indicator
E-3
B
Switch - Front Drive
D-3
B
Lamp - Start Aid
D-7
A
Switch - Heater Blower
E-4
13
Meter - Service
D-8
A
Switch - Key Start
D-7
A
Motor - Blower
D-4
9
Switch - Park Brake
D-6
24
Motor - Blower
E-6
9
Switch - Primary Steer
C-3
B
Motor - Fan As
F-7
10
Switch - Refrigerant
F-1
17
Motor - Wiper (Front)
E-3
9
Switch - Return to Dig
A-3
25
Motor - Wiper (Rear)
E-9
11
Switch - Running Lamp
E-7
A
Relay - A/C
C-9
A
Switch - Start Aid
C-2
A
Relay - Accessory
C-7
A
Switch - Start Aid
D-7
A
Relay - Cab
C-9
A
Switch - Thermostat
E-6
9
Relay - Lamp Check
C-7
A
Switch - Turn/Hazard
F-3
B
Relay - Main
C-8
A
Switch - Wiper (Front)
D-6
A
Relay - Park Brake Alarm
C-7
A
Switch - Wiper (Rear)
E-6
A
Relay - Start
C-8
A
Switch - XMSN Neutralizer
B-6
A
Resistor - Blower (A/C)
E-5
12
Tachometer
D-9
A
Printed in U.S.A.
© 1996 Caterpillar All Rights Reserved
Electrical Schematic Symbols And Definitions
Harness And Wire Electrical Schematic Symbols
13
Beacon - Magnetic
Machine locations are repeated for components located close together. A = Operator Compartment - Right Console
Schematic Machine Location Location CONN 1 A-8 6 CONN 2 B-8 26 CONN 3 B-8 26 CONN 4 B-8 26 CONN5 B-9 26 CONN 6 B-9 6 CONN 7 B-9 6 CONN8 B-6 6 CONN9 B-6 6 CONN 10 C-6 26 CONN 11 Data Link Plug A-7 8 CONN 12 Code Plug A-6 8 CONN 13 E-4 27 CONN14 C-4 26 CONN15 B-4 26 CONN 16 B-4 26 CONN 17 A-4 26 ¹ The connectors shown in this chart are for harness to harness connectors and other special connectors. Connectors that join a harness to a component are generally located at or near the component. See the Component Location Chart. Connector Number
GY
Machine Location
5BL727-1499
Connector Location¹
405
Schematic Location
446B Backhoe Loader Electrical System
Control Circuits
Not Applicable
Solenoid 1 Open Circuit Solenoid 2 Open Circuit Solenoid 3 Open Circuit Solenoid 4 Open Circuit Solenoid 5 Open Circuit Solenoid 6 Open Circuit Parking Brake Alarm Relay Open Circuit Solenoid 1 Short to Ground Solenoid 2 Short to Ground Solenoid 3 Short to Ground Solenoid 4 Short to Ground Solenoid 5 Short to Ground Solenoid 6 Short to Ground Parking Brake Alarm Relay Short to Ground Solenoid 1 Short to + Battery Solenoid 2 Short to + Battery Solenoid 3 Short to + Battery Solenoid 4 Short to + Battery Solenoid 5 Short to + Battery Solenoid 6 Short to + Battery Parking Brake Alarm Relay Short to Battery Invalid Shift Lever Input System Volatge Above Normal System Voltage Below Normal Invalid Harness Code
Primary Steering
Stop Lamp
Gauge - Converter Temp
Diagnostic Code Conversion
1-2 Normally Open 1-3 Normally Closed
9X-3395
OR
Form Number
SENR5856
Rotary Beacon
Contact Position
415 kPa (60.2 psi)
604
Related Electrical Service Manuals
Transmission and Shift Control
PK
Deactuate
Main Chassis
Monitoring Circuits
SENR3828
603
Actuate
689 ± 103 kPa (100 ± 14.9 psi)
BK
301
Starting Motor 3E-5382
Off Machine Switch Specification
Function
Lighting Circuits
Basic Machine Circuits
SENR3685
Part No.
200 276
Alternator 3E-7295 (Std 55A), 9X-0341 (Att 90A)
Monitoring Circuits (Cont'd)
Accessory Circuits
Ground Circuits
Title
SENR1243 December 1996
Description
A
AA
T
Pressure Symbol
19 22 27 9 13 21 12 5 B 14
1
11
8
10 A
Level Symbol
Flow Symbol
26
25
2
Typical representation of a Sure-Seal connector. The plugand receptacle contain both pins and sockets.
Pin or Socket Number
23 18 17 20
2 15
Wire, Cable, or Harness Assembly Identification
Normally open switch that will close with an increase of a specific condition (temp-press-etc.).
Component Part Number
Single Wire Connector
7
Normally open switch that is closed due to an applied condition, and will open again with a specific decrease in that condition.
3
6
Typical representation of a Deutsch connector. The plug contains all sockets and the receptacle contains all pins.
Receptacle
Plug
16
24 4
Temperature Symbol
1 2
1 2
1
C
A
A 325-PK-14
Pin
AA 1
325-PK-14
Wire Color
Socket
Normally closed switch that will open with an increase of a specific condition. 2
Normally closed switch that is open due to an applied condition, and will close again with a specific decrease in that condition.
9X-1123
200-BK-14
Circuit Number Identification
The circle indicates that the component has screw terminals and a wire can be disconnected from it.
Wire Gauge
Electrical Schematic Symbols And Definitions FUSE - A component in an electrical circuit that will open the circuit if too much current flows through it.
No circle indicates that the wire cannot be disconnected from the component.
4 12
11 10
9
This indicates that the component has a wire connected to it that is connected to ground. 5 B 27 13
A 24 6 1
19
REED SWITCH - A switch whose contacts are controlled by a magnet. A magnet closes the contacts of a normally open reed switch; it opens the contacts of a normally closed reed switch.
8
22 21 14 18 25 16 23 3 2620
17
7
This indicates that the component does not have a wire connected to ground. It is grounded by being fastened to the machine.
2 15
RELAY (Magnetic Switch) - A relay is an electrical component that is activated by electricity. It has a coil that makes an electromagnet when current flows through it. The electromagnet can open or close the switch part of the relay. CIRCUIT BREAKER (C/B) - A component in an electrical circuit that will open the circuit if too much current flows through it. This does not destroy the circuit breaker and it can be reset to become part of the circuit again.
B = Operator Compartment - Front Dash
Machine Harness Connector and Component Locations
T
SENDER - A component that is used with a temperature or pressure gauge. The sender measures the temperature or pressure. Its resistance changes to give an indication to the gauge of the temperature or pressure.
D85129
SOLENOID - A solenoid is an electrical component that is activated by electricity. It has a coil that makes an electromagnet when current flows through it. The electromagnet can open or close a valve or move a piece of metal that can do work. MAGNETIC LATCH SOLENOID - A magnetic latch solenoid is an electrical component that is activated by electricity and held latch by a permanent magnet. It has two coils (latch and unlatch) that make electromagnet when current flows through them. It also has an internal switch that places the latch coil circuit open at the time the coil latches.