4
4263110-Rev B 4-1
Chapter 4
Electrical
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
Test and Adjustment Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
Repair Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
Theory and Diagnostic Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
Electrical Component Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
Electrical Schematic Component Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
Electrical Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-10
Theory of Operation and Sub-Circuit Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-19
Power Circuit—Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-19
Preheat Circuit—Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-20
Preheat Circuit Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-21
Start Circuit—Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-26
Start Circuit Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-27
Run Circuit—Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-30
Run Circuit Schematic—Off Seat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-31
Run Circuit Schematic—On Seat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-35
Charging Circuit—Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-40
Charging Circuit Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-41
Mow Circuit—Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-42
Mow Circuit Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-43
Four Wheel Drive Circuit—Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-48
Four Wheel Drive Circuit Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-49
Four Wheel Drive Reverse Circuit Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-50
Cruise Control Circuit—Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-52
Cruise Control Circuit Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-53
Instrumentation Circuit—Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-55
Instrumentation Circuit Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-57
Optional Light Circuit—Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-62
Road Light Circuit Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-63
Work Light Circuit Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-64
4-2 4263110-Rev B
ELECTRICAL
4
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-65
Preheat Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-65
Start Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-66
Run Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-67
Charging Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-68
Mow Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-68
Four Wheel Drive Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-71
Cruise Control Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-73
Instrumentation Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-74
Test Switch Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-77
Optional Light Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-79
Component Tests and Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-81
Electrical System and Component Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-81
Circuit Breakers Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-82
Fuses Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-82
Diodes Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-83
Relays Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-83
Seat Time Delay Relay Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-84
Key Switch Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-84
Mow Switch Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-85
Test Switch and 4WD Reverse Switch Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-86
Light Switch Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-86
4WD Switch Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-87
Cruise Control Switch Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-88
Seat Switch Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-88
Hydraulic Oil Level Switch Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-89
Proximity Switches Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-90
Cruise Control Proximity Switches Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-91
Solenoids Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-91
Fuel Level Sensor Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-92
Park Brake Switch Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-93
Neutral Switch Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-93
Forward Switch Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-94
Front Limit Switch Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-94
Wing Limit Switches Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-95
ELECTRICAL
4263110-Rev B 4-3
4
Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-96
ECU (Engine Control Unit) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-96
Engine Speed Control Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-98
Batteries and Battery Tray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-98
Alternator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-99
Starter Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-100
Open the Instrument Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-100
Instrument Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-101
50A Circuit Breaker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-101
90A Circuit Breaker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-102
10A Engine Wire Harness Fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-102
Instrument Panel Wire Harness Fuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-103
Preheat Relay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-104
Starter Relay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-104
Relays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-105
Engine Main Relay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-106
Seat Time Delay Relay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-106
Key Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-107
Mow Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-108
Rocker Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-109
Right and Left Wing Limit Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-110
Front Limit Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-110
Park Brake Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-111
Neutral Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-111
Forward Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-112
Hydraulic Oil Level Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-112
Charge Filter Pressure Differential Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-113
Engine Oil Pressure Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-114
Engine Temperature Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-114
Coolant Temp Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-115
Engine Coolant Temp Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-116
Solenoids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-118
Indicator Lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-119
Diodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-120
Hour Meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-121
Engine Temperature and Fuel Level Gauges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-121
Indicator Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-122
Horn/Alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-123
Fuel Level Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-124
4-4 4263110-Rev B
ELECTRICAL
4
Specifications
Test and Adjustment Specifications
Repair Specifications
Specification
Resistance Across Solenoid Coil—
Front Mow Solenoid 1 Coil at 68° F
ohms 7.1 ± 10%
Resistance Across Solenoid Coil—
Front Mow Solenoid 2 Coil at 68° F
ohms 7.1 ± 10%
Resistance Across Solenoid Coil—
Left Wing Mow Solenoid Coil at 68° F
ohms 7.1 ± 10%
Resistance Across Solenoid Coil—
Right Wing Mow Solenoid Coil at 68° F
ohms 7.1 ± 10%
Resistance Across Solenoid Coil—
4WD Solenoid Coil at 68° F
ohms 7.1 ± 10%
Resistance Across Solenoid Coil—
4WD Reverse Solenoid Coil at 68° F
ohms 8.8 ± 10%
Park Brake Switch to Lever Air Gap
in. (mm) 0.063–0.125 (1.5–3.0)
Neutral Switch to Pointer Air Gap
in. (mm) 0.063–0.125 (1.5–3.0)
Forward Switch to Plate Air Gap
in. (mm) 0.063–0.125 (1.5–3.0)
Front Limit Switch to Plate on Lift Arm Air Gap
in. (mm) 0.063–0.125 (1.5–3.0)
Wing Limit Switch to Plate on Lift Arm Air Gap
in. (mm) 0.063–0.125 (1.5–3.0)
Specification
Solenoid Nut Torque lb-ft (N·m) 4–5 (5.4–6.8)
Hydraulic Oil Level Switch Torque
lb-ft (N·m) 10–15 (0.7–1.0)
ELECTRICAL
4263110-Rev B 4-5
4
Theory and Diagnostic
Information
Electrical Component Symbols
The following symbols are used in electrical schematics
to represent various electrical components.
Switches
1
1 The sample switch symbols shown are just a few of the many switch configurations. Switches are
designated by the number of “poles” (circuits controlled) and “throws” (actuator positions). Unless otherwise
specified, switches are shown in “Normally Open” (N.O.) position.
Single Pole, Single Throw
(SPST)
Double Pole, Single Throw
(DPST)
Single Pole, Double Throw
(SPDT)
Double Pole, Double Throw
(DPDT)
Proximity Switch
Switching Devices
Temperature Switch Pressure Switch
Relay
Circuit Protection Devices
Fuse Circuit Breaker
N.O.
Blk Wht
(+)
t˚
P
87 87A85
86 30
4-6 4263110-Rev B
ELECTRICAL
4
Motors and Generating Devices
Electric Motors (may also
include “AC” or “DC”)
Stator
Alternator
Actuating Devices
Solenoid Valve PTO Clutch
Engine-Related Devices
Ignition Coil Spark Plug
Regulator Fuel Shutoff Solenoid
Lights
Single-Element Light Dual-Element Light
M
G
G
U
3
U
Pull-In Hold-In
ELECTRICAL
4263110-Rev B 4-7
4
Miscellaneous Symbols
Enclosure
(cabinet, housing, etc.)
Wires (crossing but not
connected)
Ground (to earth) Wiring Connections
Ground (to chassis) Coil
Direct Current (DC)
(as shown on an oscilloscope)
Battery
Alternating Current (AC)
(as shown on an oscilloscope)
Diode
Resistor Pin and Socket Connector
(+)
(-)
4-8 4263110-Rev B
ELECTRICAL
4
Electrical Schematic Component Identification
Electrical components shown in the main schematic are identified with an alphanumeric callout. All electrical
components shown in the electrical schematic are listed below.
• A1—ECU (See Figures 4-2, 4-3, and 4-4.)
• A2—Engine Speed Control Unit (See Figure 4-7.)
• B1—Charge Filter Pressure Differential Switch
(See Figure 4-1.)
• B2—Hydraulic Oil Level Switch (See Figure 4-1.)
• B3—Engine Coolant Temp Switch (See Figure 4-1.)
• B4—Engine Temperature Sensor (See Figure 4-1.)
• B5—Fuel Level Sensor (See Figure 4-2.)
• B6—Engine Oil Pressure Switch (See Figure 4-2.)
• B7—Throttle Position Sensor (See Figure 4-7.)
• B12—EGR Lift Sensor (See Figure 4-3.)
• B13—Crank Angle Sensor (See Figure 4-3.)
• B14—Cam Angle Sensor (See Figure 4-3.)
• B15—Fuel Rail Pressure Sensor (See Figure 4-3.)
• B16—Boost Pressure Sensor (See Figure 4-3.)
• B17—Coolant Temp Sensor (See Figure 4-4.)
• B18—Air Intake Temp Sensor (See Figure 4-3.)
• B19—Fuel Temp Sensor (See Figure 4-4.)
• CB1—50A Circuit Breaker (See Figure 4-1.)
• CB2—90A Circuit Breaker (See Figure 4-1.)
• CB3—50A Circuit Breaker (Optional)
(See Figure 4-9.)
• E2—Front Left Work Light (Optional)
(See Figure 4-9.)
• E3—Front Right Work Light (Optional)
(See Figure 4-9.)
• E4—Left Side Work Light (Optional)
(See Figure 4-9.)
• E5—Right Side Work Light (Optional)
(See Figure 4-9.)
• E6—Fuel Gauge Light (Optional)
(See Figure 4-9.)
• E7—Engine Temp Gauge Light (Optional)
(See Figure 4-9.)
• E10—Left Side Tail Light (Optional)
(See Figure 4-9.)
• E11—Right Side Tail Light (Optional)
(See Figure 4-9.)
• E12—Rear Left Flasher (Optional)
(See Figure 4-9.)
• E13—Rear Right Flasher (Optional)
(See Figure 4-9.)
• E14—Front Left Flasher (Optional)
(See Figure 4-9.)
• E15—Front Right Flasher (Optional)
(See Figure 4-9.)
• E16—Left Head Light (Optional)
(See Figure 4-9.)
• E17—Right Head Light (Optional)
(See Figure 4-9.)
• E18—Center Work Light (Optional)
(See Figure 4-9.)
• F5—5A Fuse (See Figure 4-1.)
• F6—5A Fuse (See Figure 4-1.)
• F7—5A Fuse (See Figure 4-6.)
• F8—15A Fuse (See Figure 4-8.)
• F9—5A Fuse (See Figure 4-6.)
• F10—5A Fuse (See Figure 4-7.)
• F11—5A Fuse (See Figure 4-8.)
• F12—15A Fuse (See Figure 4-8.)
• F13—10A Fuse (See Figure 4-1.)
• F14—20A Fuse (Optional) (See Figure 4-9.)
• F15—20A Fuse (Optional) (See Figure 4-9.)
• F16—20A Fuse (Optional) (See Figure 4-9.)
• F17—20A Fuse (Optional) (See Figure 4-9.)
• G1—12V Battery (See Figure 4-1.)
• G2—12V Battery (See Figure 4-1.)
• G3—Alternator (See Figure 4-1.)
• H1—Indicator Module (See Figure 4-1.)
• H2—Hydraulic Oil Level Light (See Figure 4-1.)
• H3—Check Engine Light (See Figure 4-2.)
• H4—Horn (See Figure 4-1.)
• H5—Engine Temperature Gauge (See Figure 4-1.)
• H6—Fuel Gauge (See Figure 4-2.)
• J1— 8-Pin Connector (See Figure 4-1.)
• J2—12-Pin Connector (See Figure 4-1.)
• K1—Interlock Relay (See Figure 4-5.)
• K2—Run Relay (See Figure 4-5.)
• K3—Start Relay (See Figure 4-5.)
• K4—Brake Start Relay (See Figure 4-6.)
• K5—Brake Run Relay (See Figure 4-6.)
• K6—Neutral Start Relay (See Figure 4-6.)
• K7—Neutral Run Relay (See Figure 4-6.)
• K8—Neutral Cruise Control Relay (See Figure 4-6.)
• K9—Left Mow Relay (See Figure 4-8.)
• K10—Front Mow Relay (See Figure 4-8.)
• K11—Right Mow Relay (See Figure 4-8.)
ELECTRICAL
4263110-Rev B 4-9
4
• K12—Cruise Control Relay (See Figure 4-6.)
• K13—4WD Relay (See Figure 4-7.)
• K14—Preheat Relay (See Figure 4-1.)
• K15—Run Cutout Relay (See Figure 4-5.)
• K16—Auxiliary Relay (See Figure 4-5.)
• K17—Ignition Relay (See Figure 4-5.)
• K18—Starter Relay (See Figure 4-1.)
• K19—Engine Main Relay (See Figure 4-1.)
• K20—Seat Time Delay Relay (See Figure 4-6.)
• K21—Light Relay (Optional) (See Figure 4-9.)
• M1—Starter Motor (See Figure 4-1.)
• M2—Fuel Pump (See Figure 4-2.)
• M3—EGR Valve (See Figure 4-3.)
• M4—Suction Valve (See Figure 4-4.)
• P1—Hour Meter (See Figure 4-1.)
• R1—Manifold Heater (See Figure 4-1.)
• S1—Key Switch (See Figure 4-1.)
• S2—Seat Switch (See Figure 4-6.)
• S3—Mow Switch (See Figure 4-7.)
• S4—Left Wing Limit Switch (See Figure 4-8.)
• S5—Cruise Control Switch (See Figure 4-6.)
• S6—Neutral Switch (See Figure 4-6.)
• S7—Park Brake Switch (See Figure 4-6.)
• S8—Front Limit Switch (See Figure 4-8.)
• S9—Right Wing Limit Switch (See Figure 4-8.)
• S10—Forward Switch (See Figure 4-7.)
• S12—4WD Reverse Switch (See Figure 4-7.)
• S13—4WD Switch (See Figure 4-7.)
• S14—Test Switch (See Figure 4-1.)
• S18—Left Brake Pedal Switch (See Figure 4-6.)
• S19—Right Brake Pedal Switch (See Figure 4-6.)
• S21—Light Switch (See Figure 4-9.)
• V1—Diode (See Figure 4-5.)
• V2—Diode (See Figure 4-1.)
• V3—Diode (See Figure 4-1.)
• V4—Diode (See Figure 4-7.)
• X1—ECU Connector (See Figures 4-3 and 4-4.)
• X2—ECU Connector (See Figures 4-2 and 4-4.)
• X3—Diagnostic Connector (See Figure 4-2.)
• X4—Engine Speed Control Unit Connector
(See Figure 4-7.)
• Y1—Fuel Injector (See Figure 4-4.)
• Y2—Fuel Injector (See Figure 4-4.)
• Y3—Fuel Injector (See Figure 4-4.)
• Y4—Fuel Injector (See Figure 4-4.)
• Y5—Cruise Control Magnet (See Figure 4-6.)
• Y6—4WD Solenoid (See Figure 4-7.)
• Y7—4WD Reverse Solenoid (See Figure 4-7.)
• Y8—Left Mow Solenoid (See Figure 4-8.)
• Y9—Front Mow Solenoid 1 (See Figure 4-8.)
• Y10—Front Mow Solenoid 2 (See Figure 4-8.)
• Y11—Right Mow Solenoid (See Figure 4-8.)
4-10 4263110-Rev B
ELECTRICAL
4
Electrical Schematic
See Figures 4-1 through 4-9.
Figure 4-1
Blk
Red
+
-
12V
Org
Yel/Red
Gry/Yel
Gry/Yel
OrgOrg
Org
C
EB
D
AF
Wht/Vio
Wht/Vio
Org/
Blk
Org/
Blk
Org/
Blk
Org/
Blk
Org/
Blk
Org/
Blk
Red/YelRed/Yel
S1
Key
Switch
Off
Run
Glow
Start
B
I
G
S
F5
5A
Fuse
F6
5A
Fuse
F13
10A
Fuse
H1
Indicator
Module
67
Wht
712
Wht
107 Wht
112
Wht
Gry/
Ye l
712 Wht 712 Wht
59 Wht
59 Wht
59 Wht
707 Wht
59 Wht
Red
M1
Starter
Motor
M
G1
Battery
G2
Battery
CB2
90A
Circuit
Breaker
CB1
50A
Circuit
Breaker
Red
K18
Starter
Relay
59 Wht
59 Wht
Engine
Oil
Pressure
Light
603 Wht
51 Wht
604
Wht
Ye l
Ye l
Yel/BlkYel/Blk Yel/Blk
Ye l
(2) (3)
(1)
Wht/Brn
Wht/Brn
LBlu/Blk
LBlu/
Blk
LBlu/
Blk
Wht/
Brn
Wht/
Brn
708 Wht
54 Wht 54 Wht
Org/Blk Org/Blk
Org/Blk
Org/Blk
57
Wht
57
Wht
59
Wht
57
Wht
K19
Engine
Main
Relay
G
U
3
S
113
Wht
Gry/
Red
Gry/
Red
Vio/
Yel
Vio
To ECU
Terminal X2-12
(Reference Figure 4-4)
B
L
J1-1
J4-6
J1-6
J1-5
J4-5
J4-1
J2-1
J6-11
J1-2
J5-1
J4-2
J6-7
G3
Alternator
112 Wht
Blk
Blk
Blu
Blu
B2
Hydraulic Oil
Level
Switch
V2
Diode
V3
Diode
H2
Hydraulic
Oil
Level
Light
Preheat
Light
S14
Test
Switch
Alternator
LIght
Charge
Filter
LIght
Brn Brn Brn
25 PSI
On (Momentary)
Off
H4
Horn
B3
Engine
Coolant
Temp
Switch
t˚
B
G
P1
Hour
Meter
B4
Engine
Temperature
Sensor
Blk
601 Wht
+12V
SignalGnd
H5
Engine
Temperature
Gauge
Unswitched Power Circuit
Switched Power Circuit
Switched Power (Key Switch)
B1
Charge
Filter
Pressure
Differential
Switch
Blk
Blu
25 PSI
P
8787A 85
8630
K14
Preheat
Relay
R1
Manifold
Heater
8787A 85
8630
59
Wht
707
Wht
66
Wht
706
Wht
Blk
Red
+
-
12V
TN4023
ELECTRICAL
4263110-Rev B 4-11
4
Electrical Schematic
Continued
Figure 4-2
Org Org
Gry/Yel
Gry
Wht/Vio
Gry/Yel
Wht/Vio
Red/YelRed/Yel
712 Wht 712 Wht
X2-5 Starter Relay Output (-)
707 Wht 707 Wht
X2-24 Preheat Relay Output (+)
310 Wht
X2-9 Check Engine Light Output (-)
603 Wht 603 Wht
X2-6 Engine Oil Pressure Light Output (-)
51 Wht51 Wht
X2-7 Preheat Light Output (-)
706 Wht
706 Wht
706 Wht
706 Wht
706 Wht
706 Wht
706 Wht
Gnd X2-20
Gnd X2-39
Gnd X2-40
Gnd X2-59
Gnd X2-60
Gnd X2-79
Gnd X2-80
54 Wht
X2-23 Main Relay Output (-)
54 Wht54 Wht
X2-3 Main Relay Output (-)
708 Wht708 Wht708 Wht
708 Wht
710 Wht
708 Wht
X2-1 12V Power Input (+)
708 Wht
Org/Blk
Org/Blk
A1
ECU
X3
Diagnostic
Connector
J1-8
J2-8
J6-1
J6-8
J1-4
J7-21
J5-9
H3
Check
Engine
Light
BrnBrn
111 Wht
111
Wht
X2-13 Switched Power Input
111 Wht56 Wht
15 Wht
14 Wht
15 Wht
14 Wht
706 Wht
X2-33 Switched Power Input
X2-36 Diag CAN Hi
X2-16 Diag CAN Low
PnkBlk
Pnk/Wht
+12V
SignalGnd
H6
Fuel
Gauge
B5
Fuel
Level
Sensor
708 Wht708 Wht
X2-18 12V Power Input (+)
708 Wht
X2-21 12V Power Input (+)
708 Wht
X2-38 12V Power Input (+)
708 Wht
X2-58 12V Power Input (+)
708 Wht
X2-78 12V Power Input (+)
1 Wht
1 Wht1 Wht
Blk
Blk
M
M2
Fuel
Pump
708
Wht
708
Wht
Blk
LGrn
60
Wht
P
B6
Engine
Oil
Pressure
Switch
60 Wht
Engine Oil Pressure Sw Input X2-29
710 Wht
CAN Hi X2-37
709 Wht
CAN Low X2-17
709 Wht
CAN Hi 1
+12V 3
CAN Low 2
Gnd 4
Unswitched Power Circuit
Switched Power Circuit
Switched Power (Key Switch)
To K1 Interlock Relay
Terminal 87
(Reference Figure 4-5)
J4-4
Gry
TN4024
4-12 4263110-Rev B
ELECTRICAL
4
Electrical Schematic
Continued
Figure 4-3
Red/Yel Red/Yel
M
708 Wht Wht
A1
ECU Continued
Org Org
Gry/Yel
Wht/Vio
Gry/Yel
Wht/Vio
+5V
Sig
Gnd
B16
Boost
Pressure
Sensor
+5V
Sig
Gnd
B13
Crank
Angle
Sensor
+5V
Sig
R2
1K Ohm
Resistor
Gnd
B15
Fuel Rail
Pressure
Sensor
B18
Air
Intake
Temp
Sensor
+5V
Sig
Gnd
B12
EGR
Lift
Sensor
(+)
(-)
M3
EGR
Valve
+5V
Sig
Gnd
B14
Cam
Angle
Sensor
Blk
Blk
Blk
38 Wht
Boost Pressure Sensor +5V X1-48
41 Wht
Boost Pressure Sensor Gnd X1-4
42 Wht
Gry/Red
Wht/Blk
Wht/Red
Boost Pressure Sensor Signal X1-14
94 Wht
Crank Angle Sensor Gnd X1-6
Crank Angle Sensor Gnd X1-9
145 Wht
Blk
Red
Crank Angle Sensor Signal X1-29
61 Wht
Fuel Rail Pressure Sensor +5V X1-68
63 Wht
Fuel Rail Pressure Sensor Gnd X1-3
62 Wht
Blu
J7-9
J7-41
J7-6
J7-2
J7-34
J7-25
J7-33
J7-39
J7-26
J7-28
J7-40
J7-35
J7-14
J7-23
J7-29
J7-30
J7-18
J7-15
Grn
Yel
Fuel Rail Pressure Sensor Signal X1-32
62 Wht
Fuel Rail Pressure Sensor Signal X1-13
53 Wht
Air Intake Temp Sensor Gnd X1-25
52 Wht
Wht
Red
Air Intake Temp Sensor Signal X1-34
35 Wht
EGR Lift Sensor Gnd X1-24
36 Wht
Blk/Yel
Yel/Grn
EGR Lift Sensor Signal X1-36
32 Wht
EGR Motor (+) X1-80
33 Wht
EGR Motor (-) X1-60
Yel
Blk/Red
91 Wht
Cam Angle Sensor +5V X1-28
92 Wht
Cam Angle Sensor Gnd X1-27
90 Wht
Grn
Yel
Blu
Cam Angle Sensor Signal X1-8
65 Wht
Shield Gnd X1-26
Blk
94 Wht
710 Wht Grn
Ye l Ye l
Grn
709 Wht
J6-4 J5-7
J5-4J6-6
Wht
J5-12J6-12
Unswitched Power Circuit
Switched Power Circuit
Switched Power (Key Switch)
TN4025
ELECTRICAL
4263110-Rev B 4-13
4
Electrical Schematic
Continued
Figure 4-4
Grn107 Wht Grn Grn Grn
A1
ECU Continued
J8
705 Wht
705 Wht
injector #3 X1-42
Yel
Y3 Fuel Injector
703 Wht
Injector #2, #3 X1-43
LGrn6
5
4
3
2
1
8
7
J8-G
J7-1
injector #3 X1-62
703 Wht
Injector #2, #3 X1-63
LGrn
704 Wht
injector #2 X1-41
Wht/Blk
700 Wht
Injector #1, #4 X1-47
Grn
44 Wht
Fuel Temp Sensor Gnd X1-23
43 Wht
Grn/Org
Grn/Blk
Fuel Temp Sensor Sig X1-33
47 Wht 47 Wht
Suction Valve (-) X1-71
Suction Valve (-) X1-51
45 Wht 45 Wht
Suction Valve (+) X1-72
45 Wht
Suction Valve (+) X1-52
47 Wht
B19
Fuel
Temp
Sensor
40 Wht
Coolant Temp Sensor Gnd X1-5
39 Wht
Blu/Red
Blu
Coolant Temp Sensor Sig X1-15
B17
Coolant
Temp
Sensor
M
Gry
(+)
(-)
Blk/Red
M4
Suction
Valve
Start Input X2-12
Ye l Ye l
Grn Grn
Red/Yel Red/Yel
Wht Wht
Org
Gry/Yel
Wht/Vio
Gry/Yel
Wht/Vio
Y2 Fuel Injector
Y1 Fuel Injector
Y4 Fuel Injector
701 Wht
Injector #1 X1-66
Red
701 Wht
Injector #1 X1-46
702 Wht
Injector #4 X1-65
Blu/Blk
706 Wht
706 Wht Blk
700 Wht
Injector #1, #4 X1-67
Grn
702 Wht
Injector #4 X1-45
704 Wht
Injector #2 X1-61
J7-38
J7-24
J7-20
J7-7
J7-3
J7-13
J1-3 J4-3
Unswitched Power Circuit
Switched Power Circuit
Switched Power (Key Switch)
107 Wht To K-18 Starter Relay
Terminal 86
(Reference Figure 4-1)
TN4026
4-14 4263110-Rev B
ELECTRICAL
4
Electrical Schematic
Continued
Figure 4-5
Wht/
Vio
Wht/
Vio
Gry/
Yel
Gry
Grn
GrnGrn
Org
Gry/Yel
Wht/Vio
Red/Yel
8787A 85
8630
Blk
Org
Red/
Ye l
Red/
Ye l
K15
Run
Cutout
Relay
8787A 85
8630
Blk
Wht/
Vio
DBlu/
Ye l
DBlu/
Ye l
K16
Auxiliary
Relay
K17
Ignition
Relay
8787A 85
8630
Blk
Gry/
Yel
Red/
Ye l
To Fuses F6, F7, F8, F12
To Mow Switch Terminal 8
8787A 85
8630
Blk
K3
Start
Relay
Red/
Blu
Red/
Blu
Blk
87 87A85
86 30
K2
Run
Relay
Gry Gry
To
ECU Terminals X2-13 and X2-33
(Reference Figure 4-2)
Red/Yel
Ye l
Grn
Wht
Ye l
Grn
Wht
Org
Gry/Yel
Gry/
Ye l
Blk/
Wht
GryBlk
87 87A85
86 30
K1
Interlock
Relay
Gry Gry
J4-4
Org/BrnOrg/Brn
Org/
Brn
V1
Diode
Red/Blu Red/Blu
Blk/Wht
Unswitched Power Circuit
Switched Power Circuit
Switched Power (Key Switch)
TN4027
ELECTRICAL
4263110-Rev B 4-15
4
Electrical Schematic
Continued
Figure 4-6
Blk
To Mow Switch Terminal 2
2 +12V
1 Seat Switch Input
3 Output 4 Gnd
K20
Seat
Time
Delay
Relay
Ye lYe l
Grn Grn
Red/Yel Red/Yel
Wht Wht
Org
Gry/Yel
Org/
Brn
Org/BrnOrg/Brn Org/Brn Org/BluOrg/Brn
Blk
87 87A85
86 30
K5
Brake
Run
Relay
Gry/
Blu
Blk
87 87A85
86 30
K4
Brake
Start
Relay
F9
5A
Fuse
Brn/YelRed/Yel Brn/Yel
Brn/
Yel
F7
5A
Fuse
Brn/Yel Wht
Yel/Grn
Yel/
Grn
Gry/
Wht
Gry/
Wht
Wht/
Blu
Wht/Blu
Blk
87 87A85
86 30
K6
Neutral
Start
Relay
Gry/
Blu
Org/
Grn
Org/
Grn
Org/
Grn
On
Off
S2
Seat
Switch
S6
Neutral
Switch
S7
Park
Brake
Switch
Red/Blu
Blk/Wht Blk/Wht
Red/Blu
Red/
Blu
Blk
87 87A85
86 30
K7
Neutral
Run
Relay
Yel/
Grn
Vio/
Yel
Blk
87 87A85
86 30
K8
Neutral
Cruise
Control
Relay
Org/
Blu
DGrn/
Org
DGrn/Org DGrn/Red
Vio/
Yel
Wht/Blu
Vio/Yel
Vio/Yel
Wht/BluBlk
87 87A85
86 30
K12
Cruise
Control
Relay
DGrn/Wht
DGrn/Wht
DGrn/Wht
DGrn/Wht
DGrn/Wht
S5
Cruise
Control
Switch
S19
Right Brake
Pedal Switch
S18
Left Brake
Pedal Switch
Y5
Cruise
Control
Magnet
DGrn/
Wht
DGrn/
Wht
Blk
Org/
Grn
Org/
Grn
Org/
Grn
Org/Grn
Org/
Grn
N.O.
Blk
2
Wht
1
N.O.
Blk
12
Wht
Unswitched Power Circuit
Switched Power Circuit
Switched Power (Key Switch)
(1)
(3)
(6)
(4)
(5)
(B) (A)
(2)
On (Momentary)
Off
Disable (Momentary)
TN4028
4-16 4263110-Rev B
ELECTRICAL
4
Electrical Schematic
Continued
Figure 4-7
A2
Engine
Speed
Control
Unit
Ye l Ye l
Grn Grn
Red/Yel
Red/Yel
32
DGrn/Yel
Blk/WhtBlk/Wht
Yel/Blu Yel/Blu
DGrn/
Yel
Red/Yel
Wht Wht
Wht
S3
Mow
Switch
7
4
1
2
8
5
On
Off
Org/
Wht
Wht/BlkWht/Blk
Grn/Red
(1)
(3)
(6)
(4)
(5)
(2)
Pnk/Wht
Pnk/Wht
Off
S12
4WD
Reverse
Switch
S10
Forward
Switch
F10
5A
Fuse
Gry/
Blk
Gry/Blk
Gry/Blk
Wht/
Blk
Wht/
Blk
Blk
Blk Blk
87 87A85
86 30
K13
4WD
Relay
Y6
4WD
Solenoid
Pnk/
Wht
Blk
Blk
Blk
Y7
4WD
Reverse
Solenoid
V4
Diode
On
Off
S13
4WD
Switch
Wht/Blu
Blk/Wht
Org/Grn Neutral Switch
Wht/Blu Wht/Blu
Wht/Blu
Org/Grn
X4-1 Neutral Sw Input (+)
X4-10 +5V Output
X4-9 Throttle Signal Input
X4-5 Gnd
X4-3 CAN Low
X4-4 CAN Hi
X4-6
+12V
Grn
Yel
J4-10
B7
Throttle
Position
Sensor
Blu
Blu
Blk Blk
Signal
+5V
Gnd
Red/Wht
Front Limit Sw Input X4-12
Brn/Wht
Right Wing Limit Sw Input X4-2
Brn/Grn
Left Wing Limit Sw Input X4-11
N.O.
Blk
21
Wht
Unswitched Power Circuit
Switched Power Circuit
On (Momentary)
TN4029
ELECTRICAL
4263110-Rev B 4-17
4
Electrical Schematic
Continued
Figure 4-8
Yel/Blu
Red/Yel
Red/
Yel
Yel/
Blk
Red/Yel
Blk
Brn/Grn Brn/Grn
Brn/Wht
F12
15A
Fuse
Yel/
Blu
Tan/
Grn
F11
5A
Fuse
87
87A
8586
30
K9
Left
Mow
Relay
Wht/Red
Deluxe
Seat
F8
15A
Fuse
Red/Blk
Yel/Blk
Yel/Blk
Red/
Blk
Blk
Y8
Left
Mow
Solenoid
S4
Left
Wing
Limit
Switch
Blk
Brn/Wht Brn/Wht
Brn/Grn
87
87A
8586
30
K11
Right
Mow
Relay
Red
Red
Blk
Y11
Right
Mow
Solenoid
S9
Right
Wing
Limit
Switch
Blk
Red/Wht Red/Wht
Red/Wht
Tan/Grn
Tan/Grn
Tan/Grn
87
87A
8586
30
K10
Front
Mow
Relay
Vio/Wht
Vio/
Wht
Vio/
Wht
Blk
Y9
Front
Mow
Solenoid 1
Y10
Front
Mow
Solenoid 2
Blk
S8
Front
Limit
Switch
Yel/Blk
Yel/Blk
Yel/Blk
N.O.
Blk
12
Wht
N.O.
Blk
12
Wht
N.O.
Blk
12
Wht
J4-8
Switched Power Circuit
TN4030
4-18 4263110-Rev B
ELECTRICAL
4
Electrical Schematic
Continued
Figure 4-9
CB3
50A
Circuit
Breaker
F14
20A
Fuse
F15
20A
Fuse
F17
20A
Fuse
Aux
Road
Light
Connector
E16
Left
Head
Light
DBlu/Org
LBlu/Red
Vio/Pnk
Wht/Pnk Wht/Pnk Gry/Grn
Vio/
Pnk
Vio/Pnk
Vio/Pnk Vio/Pnk
Yel/Brn
Yel/
Brn
Wht/
Org
Wht/
Org
Blk/Yel
Wht/Org
Wht/Org Wht/Org
Ye l
To
CB2
Battery
Terminal
S21
Light
Switch
F16
20A
Fuse
Vio/
Pnk
Yel
LBlu/
Red
LBlu/RedLBlu/Red Tan/Blu
8787A 85
8630
Blk/
Ye l
Blk/
Ye l
Blk/
Ye l
K21
Light
Relay
E6
Fuel
Gauge
Light
E17
Right
Head
Light
Vio/
Pnk
Vio/
Pnk
Vio/
Pnk
Vio/
Pnk
E3
Front
Right
Work
Light
Vio/Pnk Vio/Pnk
Blk/
Ye l
Blk/
Ye l
E5
Right
Side
Work
Light
Vio/
Pnk
Vio/
Pnk
Blk/
Ye l
E2
Front
Left
Work
Light
Gry/
Grn
Blk/
Ye l
E4
Left
Side
Work
Light
Gry/
Grn
Blk/
Ye l
E10
Left
Side
Tail
Light
Wht/
Org
Blk/
Ye l
E12
Rear
Left
Flasher
Pnk/
Blu
Blk/
Ye l
E14
Front
Left
Flasher
Pnk/
Blu
Blk/
Ye l
E11
Right
Side
Tail
Light
Wht/
Org
Blk/
Ye l
E18
Center
Work
Light
Gry/
Grn
E7
Engine
Temp
Gauge
Light
Right 4
Left Id. 5
Right Id. 6
Flash 1
A4
Flasher
Module
B+
3 Left
(1)
(3)
(6)
(4)
(5)
(D) (C)
(2)
Work
Road
Off
Blk/
Ye l
E13
Rear
Right
Flasher
Vio/
Gry
Blk/
Ye l
E15
Front
Right
Flasher
Vio/
Gry
Unswitched Power Circuit
TN4031
ELECTRICAL
4263110-Rev B 4-19
4
Theory of Operation and
Sub-Circuit Schematics
Power Circuit—Theory of Operation
See Figures 4-1 through 4-9.
Unswitched Power Circuit
Unswitched power is available from 50A circuit breaker
(CB1) to 5A fuse (F5). The 5A fuse provides unswitched
power to key switch (S1) terminal B.
The 50A circuit breaker (CB1) also provides unswitched
power to the following:
• Auxiliary relay (K16) terminal 30
• Brake start relay (K4) terminal 30
Unswitched power is available from 90A circuit breaker
(CB2) output terminal to the following:
• Alternator battery terminal
• Starter relay (K18) terminal 30
• Preheat relay (K14) battery terminal
• 10A fuse (F13)
Unswitched power is available from 10A fuse (F13) to
engine main relay (K19) terminals 30 and 86.
Unswitched power is available to light 50A circuit breaker
(CB3) if equipped. 50A circuit breaker (CB3) provides
unswitched power to light relay (K21) terminal 30 and
20A fuse (F14). The 20A fuse provides unswitched
power to light switch (S21) terminal 2.
Switched Power Circuit
When the key switch (S1) is turned to the run position,
voltage is provided from key switch (S1) terminal I to the
interlock circuit. With the mow switch off, park brake on,
and traction pedal in the neutral position, power is
supplied from interlock relay (K1) to ECU (A1).
With the ECU powered up, the ECU provides a ground to
the engine main relay (K19) terminal 85.
The engine main relay (K19) terminal 87 provides
operating voltage to the ECU X2 connector 12-volt power
input terminals 1, 18, 21, 38, 58, 78, fuel pump (M2), and
the engine speed control unit (A2).
Switched power is also provided to the following:
• Alternator (G3) terminal S
• Ignition relay (K17) terminal 86
• Run cutout relay (K15) terminal 30
• Interlock relay (K1) terminal 86
• Neutral switch (S6)
• Park brake switch (S7)
With unswitched power provided to auxiliary relay (K16)
terminal 30 and the key switch (S1) in the run position,
voltage is provided from auxiliary relay (K16) terminal
87A to ignition relay (K17) terminal 30. With the key
switch (S1) in the run position, the auxiliary relay (K16) is
in a de-energized state.
With the key switch (S1) in the run position, voltage is
provided to ignition relay (K17) terminal 86, energizing
the relay. With the relay energized, switched power is
provided from ignition relay terminal 87 to the flowing:
• 5A fuse (F6)
• 5A fuse (F7)
• Four wheel drive switch (S13)
• 15A fuse (F12)
•15A fuse (F8)
Switched power is provided from 5A fuse (F6) to the
following:
• Indicator module (H1) terminal C
• Hydraulic oil level light (H2)
• Horn (H4)
• Engine temperature gauge (H5)
• Fuel gauge (H6)
• Hour meter (P1)
• Check engine light (H3)
With switched power provided to the gauges and hour
meter, the gauges start to operate and the hour meter
starts logging hours.
Switched power is provided from 5A fuse (F7) to the seat
switch (S2) and the seat time delay relay (K20).
Switched power is provided from 15A fuse (F12) to the
following:
• Left mow relay (K9)
• Front mow relay (K10)
• Right mow relay (K11)
Switched power is also provided from 15A fuse (F8) to
the deluxe seat connector.
4-20 4263110-Rev B
ELECTRICAL
4
Preheat Circuit—Theory of Operation
Unswitched Power Circuit
Unswitched power is available from 50A circuit breaker
(CB1) to 5A fuse (F5). The 5A fuse provides unswitched
power to key switch (S1) terminal B.
The 50A circuit breaker (CB1) also provides unswitched
power to the following:
• Auxiliary relay (K16) terminal 30
• Brake start relay (K4) terminal 30
Unswitched power is available from 90A circuit breaker
(CB2) output terminal to the following:
• Alternator battery terminal (Not illustrated)
• Starter relay (K18) terminal 30
• Preheat relay (K14) battery terminal
• 10A fuse (F13)
Unswitched power is available from 10A fuse (F13) to
engine main relay (K19) terminals 30 and 86.
Switched Power Circuit
When the key switch (S1) is turned to the run position,
voltage is provided from key switch (S1) terminal I to the
interlock circuit. With the mow switch off, park brake on,
and traction pedal in the neutral position, power is
supplied from interlock relay (K1) to ECU (A1).
With the ECU powered up, the ECU provides a ground to
the engine main relay (K19) terminal 85.
The engine main relay (K19) terminal 87 provides
operating voltage to the ECU X2 connector 12 volt power
input terminals 1, 18, 21, 38, 58, 78, fuel pump (M2), and
the engine speed control unit (A2).
Preheat Circuit
The ECU provides voltage to the preheat relay from
terminal X2-24, energizing the relay. With the relay
energized, voltage is provided through the relay contacts
to the manifold heater. ECU preheat light output terminal
X2-7 provides a ground to the preheat light, turning on
the light. The amount of time the preheat circuit is
activated is determined by air temperature.
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