SkyTrak 8042 Service Manual - Manual (Page 613)

Electrical System
9.22 Model 8042, 10042, 10054 Legacy Rev. 10/03
9.7 ELECTRICAL SYSTEM
TROUBLESHOOTING
9.7.1 Introduction
The electrical system produces, stores and distributes
electricity in the operation of the vehicle.
An engine-driven, 12-volt, 65-amp alternator, equipped
with an internal, solid-state voltage regulator, produces
electricity. Current from the alternator charges the battery
and powers electrical system components.
The battery provides power for starting the engine and
supplements the output of the alternator during periods of
peak demand.
For Serial Numbers 8042, 13198-18990,
10042, 13198-19030 & 10054 13189-19079; wiring on
the vehicle is contained within two separate wiring
harnesses, an engine harness and a cab harness.
Several multiple or “bulkhead” connectors at the end of
each harness joins the two together.
For Serial Numbers 8042, 18991 - 19987,
10042 19031 - 19987, 10054, 19080 - 19987 and
8042/10042/10054, 0160002332 & After; wiring on the
vehicle is contained within three separate wiring
harnesses, an engine harness ECM cab harness and a
cab harness. Several multiple or “bulkhead” connector at
the end of each harness joins the harnesses together.
Each wire within a harness has color-coded insulation
which is marked with a number to aid in identifying and
tracing each circuit and in making proper connections.
Fuses and relays are included with the cab harness to
help protect the electrical system and its components.
The main wiring diagrams in this section indicate
electrical circuits and components respective of their
approximate locations on the vehicle.
The information in this section has been developed from
the perspective that all wires are connected and routed
as they were when the vehicle left the factory. Take into
account any disconnected or rerouted wires before
beginning to diagnose a circuit. Refer to the wiring
diagrams to test circuits for continuity or for shorts using
a digital multimeter, analog multimeter, test light,
ohmmeter or low-reading voltmeter.
The text discusses each circuit and component, as well
as component function and replacement. Many of the
circuits have a separate diagram specific to that circuit’s
function which can be used for troubleshooting purposes.
Those same circuits also have their own troubleshooting
flow charts. Keep in mind that the various systems on the
vehicle include both electrical and hydraulic components.
What at first may appear to be an electrical problem, may
turn out to be a hydraulic problem.
Note: All of the main electrical schematics in this
section are shown in the OFF position. The individual
circuit diagrams are shown in the ON position.
9.7.2 ECM Diagnostic System
(8042, 18991 - 19987,
10042 19031 - 19987,
10054, 19080 - 19987 And
8042/10042/10054, 0160002332 &
After)
Advanced diagnostics are included to make this
Cummins engine straightforward to repair and service.
Diagnostic examination of a fault or maintenance
condition can occur through onboard or offboard
systems.
Onboard Diagnostics
• Extensive fault detection fault capability within the
ECM
• Flash-out of fault codes
• Engine function indicator light located on the left side
of the dash to indicate warning/stop
• Maintenance lamp
Offboard Diagnostics
• INSITE™, a Windows®-based reporting program
used as a service tool for this engine. It is used to
help troubleshoot and repair the engine. This tool is
capable of doing diagnostics and programming. This
tool is available from your local Cummins Distributor.
Call the Cummins Customer Assistance Center at
1-800-343-7357.
Onboard Diagnostics
a. Fault Detection
Faults are detected while the key switch is in the RUN
position, during the operation of the vehicle itself. If a fault
becomes active (currently detected) at this time, a fault is
logged in memory and a snapshot of engine parameters
is logged. In addition, certain faults may illuminate the
warning lamp (amber) or the stop lamp (red) depending
upon the severity of the active fault.