Fuse; Electrical Diagnosis - Craftsman 28906 Professional Shop Manual

ELECTRICAL SYSTEM
Fuse
The 20A fuse is located inside the seat box section of
the frame, on the left side near the deck lift shaft.
See Figure 7.24.
Figure 7.24
The solid red wire feeds the fuse with power
picked-up from the battery cable connection to
the "hot" post of the starter solenoid.
The red wire with white trace carries fused
power to the B terminal on the key switch.
A failed fuse will disable most of the tractor's
electrical system.
Remember that a failed fuse has done it's job of
protecting the rest of the circuit from an over-
load. If a fuse blows, figure-out why and correct
the core problem before returning the tractor to
service.
ELECTRICAL DIAGNOSIS
NOTE: Electrical diagnostic procedures and
tools are the same for all Cub Cadet and MTD
tractors. This section is written in a way to pro-
vide basic trouble shooting skills that can be
used on any tractor.
With a basic understanding of the behavior of electricity
and the tools used to measure that behavior, a techni-
cian can be about 80% effective at finding electrical
problems. 80% effective is not bad, but the remaining
20% of the diagnoses are the really difficult ones that
can devour the same amount of time as the easy
80%. Experience plays a big part in successfully diag-
nosing the really difficult electrical problems. Experi-
ence leads to greater understanding.
Two German Physicists, working independently during
the late 18th and early 19th centuries summarized
what they had figured-out about electricity into some
basic laws that can help a technician understand how a
system works or why it does not work. Their names
were Gustav Kirchhoff and Georg Ohm, and their laws
are named for them.
There are basically three things that a technician is
likely to test in trying to identify an electrical problem:
Volts, Resistance, and Current. To help technicians
understand the behavior of electricity, this section
begins with an explanation of:
• Basic electrical values.
• Ohm'slaw.
• Kirchhoff's current law.
• Kirchhoff's voltage law.
• How the system is wired together.
NOTE: A graphic explanation of Kirchhoff's laws
can be found at the following web site:
http :llonline.cctt.orglphysicslablcontentlphyapbl
lessonnotes/DCcircuits/lessonKirchoff.asp
The section then continues by explaining handy tools
and techniques for diagnosing electrical problems on
outdoor power equipment.
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