New Holland T8010 Manual page 1334

Charging System Diagnostic Tests
NOTE: The batteries must be fully charged and all connections clean and tight. Use a multimeter (DVOM) for these
tests. For battery testing and service, see the battery section in the service manual.
IMPORTANT: DO NOT use a self-powered test light for any of these tests. Use of a self-powered test light can
cause damage to components in this system.
WARNING: Before performing any of the electrical tests, be sure all operating controls are in neutral or
!
park lock position. This will eliminate accidental movement of the machine or start-up of power driven
equipment.
.
Test Point
1 Place transmission in
PARK.
Start engine and set at
1000 rpm.
Measure voltage at battery.
2 Place negative lead of
DVOM to battery positive
terminal and positive lead
to starter terminal 81A.
Read voltage.
3 Attach negative lead of
DVOM to starter terminal
81A and positive lead to
starter terminal 81F.
Read voltage.
4 Attach positive lead of
DVOM to B+ terminal of
alternator and negative
lead to terminal 81F of
starter.
Read voltage.
5 Measure voltage at
alternator terminal 86 (D+)
while turning various load
on and off (lights, heater
fans etc.)
6 Measure resistance
between alternator
housing and chassis
ground.
Section 55 - Electrical System - Chapter 1
A - Charging System Output Test
Good Reading
12.8-14.5 volts
If good reading, charging
system is operating
properly.
Less than 0.4 volts
If good reading, circuit is
good. Go to next test point.
Less than 0.4 volts
If good reading, circuit is
good. Go to next test point.
Less than 0.4 volts
If good reading, go to next
test point.
Voltage varies between
12.8 and 14.5 volts in
response to load applied.
If good reading go to next
test point.
Less than 1 ohm
If good reading, charging
system is operating
properly.
55-1-153
Possible Cause of Bad Reading
High resistance between battery and B+
terminal at alternator.
Go to next test point.
High resistance between battery and
starter terminal 81A. Repair/replace
wiring as needed.
High resistance in starter solenoid.
Clean connections, repair/replace as
needed.
High resistance in circuit 120A(R).
Repair/replace wiring as needed.
121E(Y) circuit between alternator (D+)
and instrument cluster connector 61,
terminal 1, or
Excitation circuit, Perform B - Excitation
Circuit (D+) Test, or
Voltage regulator
High resistance from alternator to
chassis ground. Clean surfaces
between alternator and frame. Ensure
that all mountings are clean and tight.