Cub Cadet Z-Wing - Manual (Page 85)

Cub Cadet Commercial Z-Wing
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36.7. As an example: See Figure 36.7.
• Connect the DVOM probes to two points on the
same side of a circuit (eg. between the positive
post on the battery and the trigger wire on the
starter solenoid).
• Activate the circuit (crank the starter).
• Watch the reading on the meter.
36.8. Interpretation:
• A voltage reading greater than 1 indicates resis-
tance in the circuit that deserves investigation.
• A voltage reading greater than 2 will cause per-
formance issue with the mower, and needs to be
repaired.
• Repeating the test on individual components or
portions of the circuit can help identify the
sources of resistance.
36.9. Voltage drop tests can also be used on the
ground side of the circuit.
NOTE: Resistance on the ground side is fre-
quently over-looked in diagnosis, but it can
cause as many problems as resistance on the
hot side of the circuit.
NOTE: Ground issues can manifest themselves
in multiple circuits because many positive-side
circuits share ground paths. In complex systems,
power will even hunt for ground in near-by cir-
cuits. This is typified in the automotive field by a
brake light that does not work, but the adjacent
tail light dimly when the brake pedal is
depressed.
Figure 36.7
Probes to: battery post and trigger spade
on starter solenoid
36.10.To demonstrate a voltage drop test on the
ground side of the system, the meter is con-
nected between the negative terminal on the
battery, and the ground strap on the regulator /
rectifier. See Figure 36.10.
36.11. With the starter motor turning, the ground-side
voltage drop measures only .007 VAC , indicating
a good ground path.
36.12.Sources of resistance:
• Corroded wires or terminals
• Pinched or chafed wires
• Loose terminal connections
• Inappropriate fasteners; bright zinc or zinc-
dichromate fasteners transfer voltage much bet-
ter than black oxide or oil-and-phos coated fas-
teners.
• Insulation from paint (eg. between engine and
frame).
• Burned or corroded contacts within switches or
relays.
Figure 36.10
Ground
Negative
battery
terminal