Service manual

Electrical System
10-3
Model 3606 • Origin 10/99
Introduction
The electrical system produces, stores and distributes
electricity in the operation of the vehicle.
An engine-driven, 65-amp alternator equipped with an
internal, solid-state voltage regulator produces electricity.
Current from the alternator charges the battery and pow-
ers electrical system components.
The battery provides power for starting the engine and
supplements the output of the alternator during periods
of peak demand.
The vehicle is equipped with two separate but connected
wiring harnesses, an engine harness and a cab harness.
A multiple or “bulkhead” connector at the end of each
harness joins the two together.
Each wire within a harness has color-coded insulation
and 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 wiring diagrams in this section indicate electrical cir-
cuits and components respective of their
approximate
location 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 re-routed wires before
beginning to diagnose a circuit. Refer to the wiring dia-
grams to test circuits for continuity or for shorts using a
conventional test light, ohmmeter, multimeter or low-
reading voltmeter.
The text discusses each circuit and component, as well
as component function and replacement. A brief trouble-
shooting table appears at the conclusion of this section.
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.