Cub Cadet RZT-S Series - Manual (Page 92)

RZT-S
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Wiring diagram or schematic
A wiring or a schematic diagram, and the ability to read it, are very important in troubleshooting a circuit. The dia-
gram shows how the circuit was designed and what paths the electricity is suppose to flow.
Fused jumper wires
Fused jumper wires are handy to help find bad grounds or to jump across switches for testing purposes.
Test lights
Test lights are used as a quick way to verify voltage at a
point in a circuit. Like DMMs, they come in a wide variety
from many manufacturers.
The most basic test lights simply use the current being
checked to light an incandescent lamp. These should not
be used on any equipment that has or may have solid-
state circuitry. The power necessary to light the bulb is
more than many solid-state circuits were designed to han-
dle. Components will be destroyed in the process of test-
ing them. See Figure 7.33.
IMPORTANT: If a test light is used at all, it should
have “high-impedance”, indicating that it only
takes a sample of the electricity being tested, and
illuminates an LED to indicate the presence of
power.
NOTE: Some high impedance test lights are capable of
indicating whether the current being sampled is AC
or DC.
Self-powered continuity lights
Continuity lights can indicate whether a circuit is complete or not, but they give no indication of resistance. They
are handy for finding point-break when static-timing some older engines, but have largely been replaced by DMMs.
There are some powered high-impedance test lights on the market that have a continuity feature, and some
technicians like the fact that they can be less bulky than a DMM.
Battery Jumper Cables
The obvious use of jumper cables is to jump-start equipment to get it into the shop.
NOTE: Jumper cables are not recommended for any fuel injected Kohler-powered equipment.
A clever use of jumper cables: If the technician suspects that there is resistance on the ground side of the sys-
tem, a quick-and-dirty test can be made using jumper cables:
• Connect one cable clamp to the negative post of the battery, and connect the clamp at the other end of
the same cable to the engine block.
• If there is an immediate difference in starter motor performance, use the voltage drop technique discussed
later in this section to identify the source of the resistance.
Only use fused jumper wires. If there is a short in the circuit, using an un-fused jump could
damage components in the circuit.
! CAUTION ! CAUTION
Figure 7.33
Hi impedance test light: Incandescent
GOOD test light:
CAUTION