Schematic Location E-6
Component Alarm - Travel
Component Location Machine Location 1
Component Relay - Main Power
Schematic Location D-3
Machine Location 5 5
Alternator
C-9
2
Relay - Start
C-6
Assembly - Heater Blower
C-4
3
Relay - Start Aid
C-6
5
Battery
B-9
4
Relay - Start Disable
E-9
4
Breaker- Alternator
C-9
4
Sender - Coolant Temp
C-9
2
Breaker - Lighting
D-4
5
Sender - Fuel Level
A-6
12
Breaker - Main
D-3
5
Solenoid - Boom Lower
B-5
13
Engine Ground Strap - Engine Frame to Machine Ground
B-8
6
Solenoid - Fuel Shutoff
D-9
7
Solenoid - Hi Speed Travel
B-6
14
D-4,5
5
Solenoid - Hydraulic Disable
B-6
14
Glow Plugs
C-9
7
Switch - Air Inlet Pressure
D-9
9
Ground Stud - Machine
D-8
8
Switch - Beacon
E-4
B
Group - Gauge Cluster
C-4
A
Switch - Hi Speed Travel
D-2
15
Horn - Forward
E-6
1
Switch - Horn
C-4
A
Motor - Starter
B-9
2
Switch - Interlock
B-2
10
Motor - Washer
D-9
9
Switch - Key Start
C-4
A
Motor - Wiper
B-2
10
Switch - LH Console
D-4
16
Radio
E-6
11
Switch - Oil Pressure
D-9
7
Relay - Boom Lower
A-6
5
Switch - RH Console
C-4
17
Relay - Hydraulic Disable
E-9
4
Switch - Travel
D-2
18
Relay - Lamp
E-9
4
Switch - Wiper/Washer
E-4
B
Fuses
SENR1279 June 1998
20
3
10
A
14
17
15
5
18 13
8
2
7
19
1
6
11 B
12
16
4
*Machine locations are repeated for components located close together.
9
301.5 Excavator Electrical System
11
A = Located inside of cab. B = Located inside of right console.
3YW1-UP 10
A
B
16 17
20
5
19
15
3
18 1
13
7 9
2 4
12 8
14
6
E41238
Machine Harness Connector And Component Locations
Printed in U.S.A.
© 1998 Caterpillar All Rights Reserved
Wire Number
Wire Color
101
RD
103
Wire Description Wire Number
Wire Color
Battery (+)
405
GY
Oil Pressure Signal
YL
Lighting Power
430
BU
Air Filter Signal
104
YL
Console Power
441
OR
Coolant Temp Signal
105
RD
Key Switch Power
447
PK
Fuel Level Signal
109
RD
Alternator Output (+)
C444
YL
Alternator Indicator Lamp
112
PU
Main Power Relay Output
114
RD
Forward Horn Power
500
BR
Wiper Park
117
RD
Main Breaker Output
501
GN
Wiper Signal
118
GY
Wiper/Washer Power
506
PU
Washer Signal
119
PK
Fuel Shutoff Solenoid
508
PU
Radio Speaker (+)
122
RD
Dome Lamp Power
509
WH
Radio Speaker (-)
125
OR
Boom Lower Power
A584
BU
Window Interlock Signal
130
GN
Heater Blower Power
131
BR
Solenoid Power
603
PK
Beacon Signal
135
BU
Radio Power
607
PK
Flood Lamp Relay Output
144
GN
Beacon Power Ground Circuits
E783
WH
Dead-Engine Boom Lower
H792
BR
Flood Lamp Signal
Description Power Circuits
Description
Control Circuits
BK
Main Chassis Ground
877
YL
Start-Aid Relay Output
304
WH
Start Relay Output
E953
GY
Speed-Select Signal
306
GN
Start-Disable Relay Output
G981
PU
Travel Alarm Disable
307
OR
Key Switch (Start Position)
L987
WH
Start-Aid Signal
308
YL
Key Switch (Run Position)
M927
GN
Hydraulic-Disable Relay Output
321
BR
Travel Alarm Signal
322
GY
Forward Horn Signal
A
Schematic Location
Machine Location
CONN 1
E-8
19
CONN 2
D-8
8
CONN 3
D-8
19
CONN 4
C-8
19
CONN 5
C-8
19
Connector Number
Accessory Circuits
200
Basic Machine Circuits
Connector Location1
Monitoring Circuits
Lighting Circuits
Harness And Wire Electrical Schematic Symbols
Electrical Schematic Symbols And Definitions
CONN 6 C-8 20 The connectors shown in this chart are for harness to harness connectors. Connectors that join a harness to a component are generally located at or near the component. See the Component Location Chart.
AA
Pressure Symbol
Temperature Symbol
Level Symbol
Typical representation of a Deutsch connector. The plug contains all sockets and the receptacle contains all pins.
Receptacle
Plug
T
Flow Symbol
2
1
1 2
1 2
1
Typical representation of a Sure-Seal connector. The plugand receptacle contain both pins and sockets.
Pin or Socket Number 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 C
Normally open switch that is closed due to an applied condition, and will open again with a specific decrease in that condition.
A
A 325-PK-14
Pin
AA 1
9X-1123 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.
Circuit Number Identification
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.
No circle indicates that the wire cannot be disconnected from the component.
This indicates that the component does not have a wire connected to ground. It is grounded by being fastened to the machine.
Wire Gauge
Electrical Schematic Symbols And Definitions
The circle indicates that the component has screw terminals and a wire can be disconnected from it.
This indicates that the component has a wire connected to it that is connected to ground.
200-BK-14
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. 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. 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.