SENR1243
December 1996
446B Backhoe Loader
Electrical System
5BL727-1499
©
1996 Caterpillar
All Rights Reserved
Printed in U.S.A.
Component Location
Component
Schematic
Location
Machine
Location
Component
Schematic
Location
Machine
Location
Alarm - Backup A-9 1 Resistor - Blower (Heater) D-4 13
Alarm - Park Brake C-6 A Resistor - Key Start D-7 A
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
Beacon - Magnetic 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
Gauge - Converter Temp 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
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
Machine locations are repeated for components located close together.
A = Operator Compartment - Right Console
B = Operator Compartment - Front Dash
Connector Location¹
Connector Number
Schematic
Location
Machine
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.
T
Normally open switch that will close with an increase of a specific condition (temp-press-etc.).
Normally open switch that is closed due to an applied condition, and will open again with a
specific decrease in that condition.
Normally closed switch that will open with an increase of a specific condition.
Normally closed switch that is open due to an applied condition, and will close again
with a specific decrease in that condition.
The circle indicates that the component has screw terminals and a wire can be disconnected
from it.
No circle indicates that the wire cannot be disconnected from the component.
This indicates that the component has a wire connected to it that is connected to ground.
This indicates that the component does not have a wire connected to ground. It is grounded
by being fastened to the machine.
Electrical Schematic Symbols And Definitions
Pressure
Symbol
Temperature
Symbol
Level
Symbol
Flow
Symbol
Code
Flashed
CID - FMI Description
11
No ACTIVE
Faults
Not Applicable
12
No INACTIVE
Faults
Not Applicable
31 641 - 05 Solenoid 1 Open Circuit
32 642 - 05 Solenoid 2 Open Circuit
33 643 - 05 Solenoid 3 Open Circuit
34 644 - 05 Solenoid 4 Open Circuit
35 645 - 05 Solenoid 5 Open Circuit
36 646 - 05 Solenoid 6 Open Circuit
37 683 - 05
Parking Brake Alarm Relay Open
Circuit
41 641 - 06 Solenoid 1 Short to Ground
42 642 - 06 Solenoid 2 Short to Ground
43 643 - 06 Solenoid 3 Short to Ground
44 644 - 06 Solenoid 4 Short to Ground
45 645 - 06 Solenoid 5 Short to Ground
46 646 - 06 Solenoid 6 Short to Ground
47 683 - 06
Parking Brake Alarm Relay Short
to Ground
51 641 - 03 Solenoid 1 Short to + Battery
52 642 - 03 Solenoid 2 Short to + Battery
53 643 - 03 Solenoid 3 Short to + Battery
54 644 - 03 Solenoid 4 Short to + Battery
55 645 - 03 Solenoid 5 Short to + Battery
56 646 - 03 Solenoid 6 Short to + Battery
57 683 - 03
Parking Brake Alarm Relay Short
to Battery
69 668 - 02 Invalid Shift Lever Input
71 168 - 00 System Volatge Above Normal
72 168 - 01 System Voltage Below Normal
73 650 - 02 Invalid Harness Code
Diagnostic Code Conversion
A AA
2
A AA
1
2
325-PK-14
C
A
325-PK-14
200-BK-14
T
FUSE - A component in an electrical circuit that will open the circuit if too much current flows
through it.
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.
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.
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.
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.
Harness And Wire Electrical Schematic Symbols
Socket
Pin
Pin or Socket
Number
Wire, Cable, or Harness
Assembly Identification
Single Wire
Connector
Circuit Number
Identification
Wire
Gauge
Wire
Color
Plug
Receptacle
9X-1123
Component
Part Number
Electrical Schematic Symbols And Definitions
1
1
1
2
2
Typical representation of a
Sure-Seal connector. The
plugand receptacle contain
both pins and sockets.
Typical representation of a
Deutsch connector. The
plug contains all sockets
and the receptacle contains
all pins.
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.
Related Electrical Service Manuals
Form Number
SENR3685
SENR3828
SENR5856
Title
Alternator
3E-7295 (Std 55A),
9X-0341 (Att 90A)
Starting Motor 3E-5382
Transmission and Shift Control
Resistor And Solenoid Specifications
Component Part No. Resistance (Ohms)¹
Resistor - A/C Blower 7T-3828
Overall - 1.0 ± .1;
Tap - .5 ± .05
Resistor - Key Switch 8C-4110 22 ± 1.1
Solenoid - A/C Clutch 7T-7825 3.5 ± 0.15
Solenoid - Bucket Positioner 3E-8620 32.1
Solenoid - Front Drive 6T-6885 8.9 ± 0.3
Solenoid - Start Aid 3T-9493 1.5
Relay - Start 3E-9362 90 ± 9
¹ At room temperature.
Off Machine Switch Specification
Part No. Function Actuate Deactuate Contact Position
9X-3395 Primary Steering
689 ± 103 kPa
(100 ± 14.9 psi)
415 kPa
(60.2 psi)
1-2 Normally Open
1-3 Normally Closed
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
Wire Description
Wire
Number
Wire
Color
Description
Wire
Number
Wire
Color
Description
Power Distribution Circuits
Monitoring Circuits (Cont'd)
101 RD Bat (+) 447 PK Fuel Level Gauge
102 BU Hd Lmp 450 YL Tach Sender (+)
103 YL Aux Ckt 483 BR Brake Fluid Level
105 BR Key SW Accessory Circuits
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 Lighting Circuits
Ground Circuits 603 PK Rotary Beacon
200 BK Main Chassis 604 OR Stop Lamp
202 BK XMSN Ctrl 605 YL Turn Lamp - Left
276 BK XMSN Ctrl ldent Code 0 606 GY Turn Lamp - Right
277 BK XMSN Ctrl ldent Code 1 608 GN Flood Lamp - Rear
278 BK XMSN Ctrl ldent Code 2 610 OR Head Lamp Basic
278 BK XMSN Ctrl ldent Code 3 614 PU Park/Tail/Dash Lamp
280 BK XMSN Ctrl ldent Code 4 617 BR Tail/Position Lamp - Left (Road Pkg)/Width
281 BK XMSN Ctrl ldent Code 5 618 YL Tail/Position Lamp - Right (Road Pkg)/Width
Basic Machine Circuits 620 WH Flood Lamp - Front
301 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 Control Circuits
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
Monitoring Circuits 944 OR Data Link + (CAT)
405 GY Opr Mon Oil Press. (Lo Setting) 945 BR Data Link - (CAT)
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+)
A
3
4
5
6
8
9
10
11
12
14
15
13
16
B
1
2
17
18
19
20
21
22
23
24
26
27
7
A
3
4
5
6
8
11
13
16
B
1
2
17
20
21
24
25
26
27
7
Machine Harness Connector and Component Locations
D85129
25
10
9
12
22
18
19
14
23
15
944-OR
975-WH
958-YL
751-GN
901-WH
755-OR
900-PU
754-BU
752-YL
C920-GY
281-BK
280-BK
279-BK
278-BK
277-BK
276-BK
202-BK
E999-GN
969-YL
UNUSED
SOLENOID RETURN
UNUSED
PARK BK ALARM
SPEED 4 SOLENOID
SPEED 3 SOLENOID
SPEED 2 SOLENOID
SPEED 1 SOLENOID
REV SOLENOID
FWD SOLENOID
ACTION LAMP
HARNESS CODE 5
1
2
3
21
4
5
6
7
8
9
10
12
13
14
15
16
17
18
19
20
11
HARNESS CODE 4
HARNESS CODE 3
HARNESS CODE 2
HARNESS CODE 0
UNUSED
UNUSED
UNUSED
UNUSED
966-GY
REV PAR (+B IN)
FWD PAR (+B IN)
SPEED 4 SW IN
SPEED 3 SW IN
SPEED 2 SW IN
970-GN
SPEED 1 SW IN
REV SW TO GND IN
FWD SW TO GND IN
UNUSED
UNUSED
22
23
24
25
8
7
26
27
28
29
L14
L28
L28
L28L28
L29
30
L29
32
L29
L29
L45
DATA LINK -
DATA LINK +
L3
945-BR
200-BK-16 200-BK
200-BK
UNUSED SPEED DR
200-BK-10
UNUSED SPEED IN
200-BK
XMSN CONTROL
121-6842
UNUSED SPEED IN
UNUSED
307-OR
306-GN
126-PK-16
33
34
200-BK
417-GY
DE
L11
128-PK
483-BR
447-PK
126-PK
C920-GY
126-PK
1
4
35
36
37
38
126-PK-16
202-BK
321-BR
39
40
31
971-YL
972-BU
965-WH
968-BR
945-BR
944-OR
6
5
HARNESS CODE 1
PARK BK SW IN
GROUND
202-BK
202-BK
419-YL
202-BK
126-PK
4
SHIFT
CONTROL
109-7393
9
7
6
5
4
3
2
1
REAR WIPER
SW
7T-9303
B
H
L
P W
B
2
8
E
D
3
6
311-WH
276-BK
277-BK
278-BK
279-BK
280-BK
281-BK
202-BK
E
C920-GY
Z
10
L7
L7
L7
L7
L17
L38
L39
202-BK
9
8
7
6
5
4
310-PU
3
2
1
+BATT (12V)
126-PK
409-OR
321-BR
M
P
307-OR
306-GN
1
2
202-BK
521-YL
522-WH
200-BK-12
120-YL-12
202-BK
5
720-PU
972-BU
971-YL
966-GY
970-GN
965-WH
968-BR
969-YL
E999-GN
202-BK
7
119-PK
119-PK
419-YL
202-BK
552-WH
405-GY
406-PU
MOTOR
113-OR
143-BR
536-WH
+BAT (12V)
6
UNUSED
321-BR
128-PK
322-GY
200-BK-10
200-BK
101-RD-10
101-RD-10
NEUTRAL
202-BK
BACKUP ALARM
KEY SW
START RELAY
GROUND
NEUTRALIZER SW
L17
L25
L16
L12
L12
L23
L22
L22
L19
L19
5
L19
L18
119-PK
K
K
L18 L18
101-RD-10
4
G
E
N
D
M
321-BR
E
E G
FIRST GEAR
SECOND GEAR
UNUSED
L40
L25
E
M
3
3
K
2
K
K
K
1
1
119-PK
K
K
720-PU
2
E
202-BK
UNUSED
161-PK-16
UNUSED
FOURTH GEAR
128-PK
THIRD GEAR
322-GY
640-GN
639-WH
605-YL
606-GY
122-BU-10
419-YL
8
BK-14
BLOWER
MOTOR
3E-7501
Z
REVERSE
415-GN
K
119-PK
200-BK
200-BK-16
200-BK-12
P
OPERATOR STATION
202-BK
E
TRANSMISSION
NEUTRALIZER SW
8T-8756
1
2
3
4
5
128-PK
126-PK
126-PK
L40
119-PK
FRONT
WIPER SW
7T-9303
BUCKET
POSITIONER
SOLENOID
3E-8620
E
OR-14
128-PK
L12
304-WH-10
2
1
6
322-GY
7
8
Z
L28
126-PK
200-BK
306-GN
307-OR
E
720-PU
321-BR
E
E
TO PLATFORM
503-BR
118-GY
505-BU
504-YL
500-BR
501-GN
502-OR
BK
BK 128-PK
762-YL
118-GY
310-PU
311-WH
B
B
H
L
W
P
505-BU
504-YL
503-BR
OPERATOR STATION
118-GY
751-GN
900-PU
755-OR
901-WH
FORWARD
FORWARD PARITY
REVERSE PARITY
754-BU
975-WH
126-PK
D
311-WH
326-PU
443-YL
441-OR
450-YL
309-GY
406-PU
405-GY
E
L45
L16
118-GY
752-YL
E
2
1
CONN 14
CONN 15
CONN 16
CONN 17
202-BK
945-BR
944-OR
126-PK
J
H
G
F
C
B
E
D
A
L45
L45
L45
E
E
ACTION
LAMP
3E-8679
126-PK
126-PK
B
B
G
G
101-RD-10
H
H
307-OR
200-BK
200-BK
E
CODE
PLUG
L11
L11
L11
L18
L25
L12
L12
L22
L23
L30 L30
L30
L34
L34
L35
L35
L35
L35
L36
L36
L36
L36
L36
L37
L37L37
L37
L38
L39
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
112-PU-10
200-BK
L18
K
H
120-YL-12
310-PU
B
126-PK-16
H
307-OR
200-BK
200-BK
200-BK
161-PK-16
H
202-BK
200-BK
304-WH-10
START
RELAY
3E-9362
536-WH
200-BK
119-PK
502-OR
501-GN
500-BR
504-YL
505-BU
118-GY
102-BU
503-BR
101-RD-12
M
LAMP CHECK
RELAY
7X-1379
H
H
H
H
87
87a
87a
87
30
86
85
303-BR
200-BK
L41
B
308-YL
308-YL
308-YL
M
105-BR-16
415-GN
ACC RELAY
7X-1379
200-BK
101-RD-10
306-GN
307-OR
MAIN
RELAY
7X-1379
K
308-YL
308-YL-16
K K
310-PU-16
309-GY
614-PU
308-YL
109-OR-10
161-PK-16
143-BR
200-BK
200-BK
308-YL
102-BU
102-BU-16
304-WH-10
101-RD-10
101-RD-10
109-OR-10
PARK BRAKE
ALARM
110-8046
E
H
620-WH-16
610-OR-16
603-PK
608-GN-16
630-GY-16
441-OR
443-YL
447-PK
450-YL
310-PU-16
309-GY
200-BK-16
536-WH-16
161-PK-16
307-OR
415-GN
H
306-GN
H
128-PK
113-OR
143-BR
126-PK
618-YL
143-BR
415-GN
1
H
2
103-YL-16
157-YL
101-RD-12
202-BK
103-YL-16
L1
K
958-YL C
103-YL-16
L40
113-OR
H
H
E
E
K
KEY SW
3E-7341
A
303-BR
A
112-PU-10
200-BK
K
E
H
E
B
A
128-PK
K
103-YL-10
E
B
B
200-BK
A/C
RELAY
7X-1379
101-RD-10
REAR HORN
30
30
87
568-GN
12
87
87a
87a
85
85
3
L41
K
L35
86
86
11
10
9
8
7
6
5
4
3
2
1
K
K
309-GY
12
11
10
9
450-YL
4
5
958-YL
6
BACKUP
ALARM
102-9236
H
307-OR
T
S
STOP/
TAIL
LAMP
3E-7398
FLOOD
LAMP
9X-6853
640-GN
618-YL
200-BK
441-OR
630-GY
326-PU
202-BK
202-BK
194-GN-10
568-GN
443-YL
103-YL-16
8
200-BK
608-GN
7
128-PK
161-PK-16
STOP LAMPS
HAZARD LAMPS
85
568-GN
H
M
308-YL
121-YL
86
30
87
536-WH-16
87a
H
PRK BRK ALARM
RELAY
7X-1379
30
86
85
202-BK
H
H
113-OR
116-BR-12
119-PK
WARNING HORN
113-OR
K
10A
XSMN CONTROL
200-BK-16
M
H
101-RD-10
112-PU-10
10A
200-BK
FLOOD
LAMP
9X-6853
OPERATOR STATION
RESISTOR
8C-4110
307-OR
15A
DIODE
8C-5444
15A
ACC
A
ST
ON
OFF
B
S
6
5
FRONT DRIVE
4
321-BR
3
49A
BACKUP ALARM/BEACON
OUT (LAMP)
+ BATTERY
GROUND
31
49
30
86
2
FLASHER
7T-4848
1
157-YL
MONITOR LAMPS
122-BU-12
12
11
10
PANEL
LAMP
8L-9801
9
8
85
87a
87
30
7
6
86
5
4
101-RD-12
3
2
1
194-GN-10
C
KEY
R
105-BR-16
HEATER
CAB
RELAY
7X-1379
85
M
617-BR-16
447-PK
126-PK-16
128-PK
200-BK-16
87a
87
122-BU-12
306-GN
608-GN-16
618-YL
617-BR
630-GY-16
620-WH-16
610-OR-16
C
B
A
603-PK
200-BK-16
610-OR
620-WH
606-GY
605-YL
640-GN
639-WH
122-BU-10
606-GY
603-PK
620-WH
610-OR
617-BR
608-GN
639-WH
630-GY
605-YL
200-BK-16
200-BK
200-BK
200-BK
605-YL
640-GN
639-WH
608-GN-16
618-YL
617-BR
620-WH-16
630-GY-16
20A
15A
126-PK
161-PK-16
610-OR-16
10A
10A
10A
10A
10A
128-PK
113-OR
123-WH
121-YL
116-BR-12
118-GY
119-PK
FRONT FLOOD
BUCKETPOS/HORN
FRONT WIPER
REAR WIPER
REAR FLOOD
GAGES
RUNNING LAMP
BREAKER
3T-2662
15A
20A
10A
K
606-GY
603-PK
101-RD-10
NOTE D
C
B
A
122-BU-10
101-RD-10
306-GN
307-OR
326-PU
326-PU
101-RD-10
M
K
DATA
LINK
PLUG
101-RD-12
-
+
568-GN
H
CONN 1
CONN 2
CONN 3
CONN 4
CONN 5
CONN 6
CONN 7
CONN 8
CONN 9
CONN 11
CONN 12
CONN 10
116-BR-16
ATTACHMENT REAR FLOOD LAMP SW
REAR FLOOD
LAMP SW
3E-7268
116-BR-12
116-BR-16
630-GY-16
608-GN-16
6
4
3
1
5
2
L27
TO
PLATFORM
TO
PLATFORM
TO
PLATFORM
T
T
W/ATCH HARNESS AS. T CONNECT
HARNESS AS. B AND BEACON
9X-8079 AS SHOWN
603-PK
MAGNETIC
BEACON
9X-8079
B
200-BK-16
603-PK-16
RD
BK
T
V
V
V
V
4
5
200-BK-16
Y
Y
BK-14
B
B
B
B
B
B
B
G
A
SEND
T
603-PK-16
SOCKET AS.
9R-7941
L27
L27
L31
L31
L38
L38
L37L44
L42 L42
L42
L43
L43
L43
L34
L34
L30
L30
H
H
H
H
H
H
H
H H
H
H
H
H
H
200-BK
441-OR
200-BK
200-BK
443-YL
200-BK
200-BK
200-BK
200-BK
441-OR
443-YL
447-PK
123-WH
123-WH
123-WH
123-WH
123-WH
123-WH
200-BK
200-BK
200-BK
200-BK
H
L41
L39
614-PU
119-PK
H
123-WH
B
L41
603-PK
608-GN-16
450-YL
B
H
310-PU-16
L44
H
A
116-BR-16
116-BR-16
H
2
FRONT FLOOD
LAMP SW
3E-7270
NOTE E
2 1
620-WH-16157-YL
H
H
H
TO
PLATFORM
2
630-GY-16
608-GN-16
2 1
610-OR-16
L42
614-PU
COOLANT
TEMP GAUGE
3E-8535
VOLTMETER
3E-8533
SERVICE
METER
6T-7337
TACHOMETER
3E-3507
450-YL
200-BK
116-BR-12
614-PU
614-PU
123-WH
157-YL
614-PU
START
AID SW
3E-7272
614-PU
614-PU
200-BK
TO RADIO
119-PK
S
CONNECT HARNESS AS. S TO HARNESS
AS. B AND BEACON 9R-8250 AS SHOWN
603-PK-16
603-PK
FIXED
BEACON
9R-8250
603-PK-16
200-BK
B
S
S
200-BK
200-BK
200-BK
200-BK
200-BK
A
B
608-GN
A
OR-16
BR-16
614-PU
614-PU
630-GY
630-GY-16
447-PK
603-PK
123-WH
H
MOTOR
TO
PLATFORM
123-WH
FLOOD
LAMP
9X-6853
STOP/
TAIL
LAMP
3E-7398
T
S
200-BK
200-BK
200-BK-16
200-BK
B
605-YL
610-OR
620-WH
639-WH
200-BK
617-BR
617-BR
639-WH
200-BK-16
610-OR
FAN AS.
5D-2855
119-PK
RD
OR-14
RD-14
308-YL-16
116-BR-12
GY-16
GN-16
605-YL
620-WH
608-GN
200-BK
1
1
200-BK-16
S
S
H
200-BK
OPERATOR STATION
OPERATOR STATION
REAR WIPER
MOTOR GP
3E-7566
C
B
BK-16
L
H
MOTOR
A
450-YL
A
610-OR-16
2
200-BK
1
603-PK
200-BK-16
200-BK
630-GY
FLOOD
LAMP
9X-6853
BK
614-PU
102-BU-16
H
H
H
H
H
H
H
200-BK
614-PU
H
200-BK
H
H
H
CONV
TEMP
GAUGE
U3E-8534
200-BK
H
200-BK
H
FUSE
HOLDER
9W-2035
NOTE C
- +
447-PK
- +
SIG
IGN
SEND
GRD
IGN
SEND
GRD
IGN
SEND
GRD
IGN
GRD
LAMP
8M-6176
REAR FLOOD
LAMP SW
3E-7270
NOTE E
BEACON SW
3E-7270
LAMP
8M-6176
LAMP
8M-6176
443-YL
LAMP
8M-6176
618-YL
617-BR-16
200-BK
RIGHT TAIL LAMP
LEFT TAIL LAMP
119-PK
441-OR
LAMP
8M-6176
H
10A
10A
504-YL
505-BU
503-BR
119-PK
119-PK
603-PK-16
603-PK
FIXED
BEACON
9R-8250
123-WH
121-YL
200-BK
614-PU
L
102-BU-16
102-BU-16
6
620-WH-16
NOTE E
3
503-BR
RUNNING
LAMP SW
3E-7268
505-BU
504-YL
L30
L30
5
3
6
4
H
FUEL GAUGE
3E-8532
2
1
200-BK
450-YL
5
4
L43
K
D88654
1
GND
B+
P
T
°
MOTOR
L
H
BR-16
GY-16
BK-16
OR-16
GN-16
5
3
6
2
4
L26
6
D
2
1
L L
L
L
L
L
L
L
B
B
M
5
4
1
2
3
L6
B
BK-16
GN-16
RD-16
WH-16
200-BK
502-OR
500-BR
639-WH
640-GN
604-OR-16
536-WH
200-BK
605-YL
128-PK
322-GY
L6
118-GY
419-YL
113-OR
143-BR
606-GY
113-OR
405-GY
L
12
A
YL-16
E
A
L26
L31
L7
L7
406-PU
419-YL
OR-16
143-BR
113-OR
405-GY
606-GY
BK
BK
605-YL
200-BK
L6
LEFT TURN
IND LAMP
8M-6176
620-WH
FLOOD
LAMP
9X-6853
620-WH
200-BK
TURN/HAZARD SW
9X-9547
200-BK-16
610-OR
FLOOD
LAMP
9X-6853
TURN
LAMP
3E-7500
610-OR
200-BK
605-YL
200-BK
606-GY
501-GN
113-OR
483-BR
ENGINE OIL
PRESS LAMP
8M-6176
RIGHT TURN
IND LAMP
8M-6176
COOLANT
TEMP LAMP
8M-6176
PARK BRAKE
LAMP
8M-6176
113-OR
113-OR
552-WH
9D-2868
9D-8047BASE
LENS
200-BK
FRONT DRIVE
LAMP
8M-6176
2
1
406-PU
128-PK
322-GY
FORWARD
HORN SW
3T-2357
ENGINE
SHUTDOWN
SOL
8C-3662
326-PU
200-BK-10
TO
ENGINE
BLOCK
FRONT WIPER
MOTOR GP
3E-7394
552-WH
301-BU-10
BRAKE FLUID
LAMP
8L-9801
DOME
LAMP
4M-3601
BK
WH
OPERATOR STATION
521-YL
521-YL
521-YL
522-WH
513-OR
REFRIGERANT SW
9D-6888
NOTE A
513-OR
AIR
CONDITIONER
CLUTCH
SOL
7T-7825
L
FRONT DRIVE
SW
3E-7270
START
GND
STOP
113-OR
L
552-WH
M
A
M
D
200-BK-10
D
D
16 GA
B
L14
L14
L3
L3
L3
D
L3
D
D
L3
L2
D
200-BK
E
1
2
200-BK
BK-16
483-BR RD-16
D
G
D
EE
DD
TO
ENGINE
BK-6
CCCC
BK-00
TO
FRAME
2
PRIMARY STEER LAMP
8L-9801
1
417-GY
DD
BRAKE SW
9W-4139
200-BK
417-GY
BK 1
F
2
BK-6
D
D
FF
ALT
3
RD
BU
PRIMARY
STEER SW
9X-3395
901-WH
D
2
G G
B
B
G
D
1
D+
R
B+
GND
BASE
LENS
BB
L2
AA
322-GY
200-BK
200-BK
620-WH
L2
L1
E
D
606-GY
200-BK-16
610-OR
620-WH
FLOOD
LAMP
9X-6853
B
975-WH
754-BU
975-WH
754-BU
752-YL
975-WH
752-YL 751-GN
975-WH
751-GN
900-PU
900-PU
755-OR
975-WH
755-OR
901-WH
975-WH
NO. 2 SOL
(FORWARD)
3E-6268
BAT
MTR
762-YL
322-GY
200-BK
200-BK
610-OR
200-BK
200-BK
2
TO
ENGINE
1
2
9D-8047
2
1
NO. 3 SOL
(FOURTH GEAR)
3E-6268
NO. 4 SOL
(FIRST GEAR)
3E-6268
L7
1
TO
ENGINE
2
975-WH
D
D
2
1
RD-00
RD-00
BK-00
BK-00
101-RD-216 GA
16 GA
BATTERY
3T-5760
BATTERY
3T-5760
NEG POS NEGPOS
D
CC
D
F
NO. 5 SOL
(SECOND GEAR)
3E-6268
16 GA
16 GA
9D-2868
FLOOD
LAMP
9X-6853
TURN
LAMP
3E-7500
1
2
1
X
101-RD-10
16 GA
16 GA
NO. 6 SOL
(THIRD GEAR)
3E-6268
D
B
G
1
2
ENGINE
OIL SW
7W-1238
D
D
101-RD-10
101-RD-10
311-WH
BB
200-BK
309-GY
BK
BK
2
1
310-PU
311-WH
START AID
SOL
3T-9493
301-BU-10
MOTOR
D
450-YL
STARTER
3E-5382
304-WH-10
FORWARD
HORN
7T-0635
441-OR
S
G
200-BK
X
311-WH
405-GY
406-PU
405-GY
RD-00
326-PU
443-YL
START AID
SW
9W-1520
BB
TO
FRAME
AA
NO. 1 SOL
(REVERSE)
3E-6268
CONVERTER
SENDER
4W-9972
200-BK-10
200-BK
200-BK
113-OR
AA
101-RD-2
16 GA
16 GA
16 GA
16 GA
ALTERNATOR
55A 3E-7295 STD
90A 9X-0341 ATCH
FRONT DRIVE
SOLENOID
6T-6885
552-WH RD-16
RD-16
301-BU-10
D
200-BK406-PU
COOLANT SW
6T-2665
COOLANT
SENDER
4W-9972
441-OR
RETURN
TO DIG SW
9G-2795
°T
°T
°T
443-YL
°T
200-BK
EE
16 GA
309-GY
450-YL
FF
C-9
D-9
E-4
WITH ATTACH BEACON REPLACE 10A FUSE WITH
15A FUSE
FUSES 10A-9W-1442 15A-9W-1441 20A-9W-1446
NORMALLY CLOSED WHEN BRAKE IS DEPRESSED
NORMALLY CLOSED AT PROPER REFRIGERANT CHARGE
A-2
A-3
A-3
A-2
A-2
B-6
B-1
F-8
F-8
C-3
C-3
01
01
00
00
01
01
01
00
V
T
S
ATCH
ATCH
ATCH
ATCH
4D-6565
F-1
ATCHE-701
F-9
D-1
C-4
B-6
E-4
B-7
ATCHP
ATCH
ATCH
ATCH
ATCH
ATCH
NOTE
LOC
01
01
02
9R-7939
7T-3550
9R-8625
106-1689
9R-9555
122-6036
126-1780
122-6034
122-6035
9R-8619
8R-6892
00
EE
DD
L
04
01
02
01
01
02
K
H
G
E
D
9R-6859
01
B
01
8Y-7236
1V-1151
01
9R-7958
Z
BB
L# CIRCUIT GROUPING
DESIGNATION
9R-8722
Y
9R-6501
X
N
M
9R-9607
9R-6500
A
7P-6682
AA
01
CC
NOTE D:
NOTE B:
THIS SCHEMATIC IS FOR THE 446B BACKHOE
(105-3504 CHG 01)
CABLE AS.
WIRE AS.
HARNESS AS.
LOCPART NO.IDENT
ATCH WIRE, CABLE,
COMPONENT
CIRCUIT NOT CONNECTED
CIRCUIT CONNECTED
BLUE
GREEN
BU
GN
RD
WH
OR
YL
PK
BK
BLADE, SPADE, RING,
OR SCREW TERMINAL
INTERNAL ELECTRICAL
CONNECTION TO SURFACE
OF COMPONENT
ELECTRICAL CONNECTION
TO VEHICLE STRUCTURE
CONNECTOR
SYMBOL DESCRIPTION
BROWN
PURPLE
GRAY
BLACK
COLORABBREV
PINK
YELLOW
ORANGE
WHITE
RED
BR
PU
GY
NOTE A:
COMPONENTS ARE SHOWN INSTALLED ON A FULLY
OPERABLE MACHINE WITH THE KEY AND ENGINE OFF,
AND XMSN SHIFTER IN NEUTRAL
UNLESS OTHERWISE SPECIFIED: ALL WIRE IS 18 GAUGE
9R-9554
3E-9093
9R-9606
NOTE
NOTE C:
CHG
B-7
A-4
04
B-4
B-4
C
F
FF 128-2874
A-8
B-7
00 B-2
E-7 NOTE E: WHEN ATACHMENT FRONT & REAR FLOOD LAMPS,
9X-6853, ARE INSTALLED ADD ATACHMENT FRONT
FLOOD LAMP SWITCH, 3E-7270. ALSO REMOVE
STANDARD REAR FLOOD LAMP SWITCH, 3E-7270,
AND REPLACE WITH 3E-7268 SWITCH.
415-GN
L14
568-GN
405-GY
406-PU
417-GY
483-BR
F
200-BK
417-GY
113-OR
447-PK
483-BR
8
1
12
11
10
2
N/O
N/C
1
3
C
3
4
5
6
7
9
P
604-OR
161-PK-16
L27
L26
L26
604-OR
E
604-OR-16
L25
L39
N
N
N
N
L39
L39
522-WH
520-WH-12
552-WH
322-GY
143-BR
405-GY
E
113-OR
200-BK-12
502-OR
500-BR
118-GY
501-GN
200-BK
200-BK-12
L25
200-BK-12
605-YL
606-GY
405-GY
113-OR
605-YL
606-GY
406-PU
419-YL
128-PK
605-YL
606-GY
639-WH
640-GN
RESISTOR
7T-3828
515-GY-12
516-GN-12
406-PU
322-GY
200-BK
200-BK
N
113-OR
122-BU-10
515-GY-12
200-BK-12
517-BU-12
HEATER
BLOWER SW
6P-3236
122-BU-10
200-BK-12
417-GY
4F
L17
L16
3F
200-BK-12
202-BK
2F
1F
N
102-BU
1R
2R
3R
4R
12V
OUTPUTS
TO
GND
SOL
RET
P
B
U
P
S
T6
LE
P
102-BU
200-BK
200-BK
102-BU
54
P
321
SOLENOID
GEAR
P
E
L16
N
L
L
L16
L
417-GY
L38
419-YL
417-GY
200-BK
200-BK
128-PK
L16
161-PK-16
B
A
A
B
2
E
536-WH
200-BK
200-BK
417-GY
C
PARK
BRAKE SW
6T-5925
419-YL
E
503-BR
505-BU
504-YL
119-PK
102-BU
161-PK-16
OPERATOR STATION
E
E
F
F
P
415-GY
9
FUEL
SENDER
6T-0454
447-PK
552-WH
143-BR
BRAKE SW
6T-5925
NOTE B
521-YL
11
10
P
102-BU-16
3
4
5
2
1
6
3
1
5
483-BR
DIODE BLOCK AS
112-4735
BLOWER
3E-7501
3
4
5
2
4
BLOWER SW
6P-3236
RESISTOR
7T-3828
517-BU-12
516-GN-12
515-GY-12
120-YL-12
520-WH-12
2
7
102-BU
1
200-BK
8
10A
515-GY-12
FUSE HOLDER
4K-5122
124-GN-12
MOTOR
E
BK-14
E
E
C
A
12
B
N
P
P
P
TO
PLATFORM
THERMOSTAT SW
3E-5465
OR-14
10A FUSE 3K-8782
20A FUSE 8M-0546
20A 124-GN-12
522-WH
200-BK-16
°T
CONN 13
C
B
A
23
1
1
3 2
F
E
D
456
6 5 4
789
C
B
A
D
9 8 7
E
F
WIRES THAT HAVE BATTERY VOLTAGE
WHEN THE KEY SWITCH IS OFF.
WIRES THAT HAVE BATTERY VOLTAGE
WHEN THE KEY SWITCH IS ON.
STARTING CIRCUIT.
GAUGE CIRCUIT.
MONITOR CIRCUIT. (EMS)
PANEL LAMP CIRCUIT.
WASHER/WIPER CIRCUIT.
HEATER AND AIR CONDITIONER CIRCUIT.
GROUND CIRCUIT.
TURN SIGNAL CIRCUIT.
ENGINE SHUTDOWN CONTROL CIRCUIT.
START AID CIRCUIT.
TRANSMISSION CONTROL CIRCUIT.
ALL DASHED LINES ARE ATTACHMENTS.
