New Holland CX720 Repair Manual page 2312

Engine starter - Testing (B.80.A.82 - G.40.A.20)
N° Test Point
1 Measure for 12 volts at B+ terminal
of 12 V Starter.
2 Ignition Switch in "START" position.
Measure for 12 Vat S terminal of 12
V Starter.
3 Ignition Switch in "START" position.
Measure for 12 volts at Start Relay
(pin 87).
4 Ignition Switch in "OFF" position.
12 V Battery Switch Open.
Measure resistance from 12 V Bat-
tery Switch (pin 2) to ground.
5 12 V Battery Switch Closed.
Measure resistance from 12 V Sys-
tem Batteries B- terminal to ground.
6 Set DVOM to read voltage.
Attach positive lead to battery posi-
tive terminal.
Attach negative lead to B+ terminal
of 12 V Starter.
Turn key to "START" position.
Less than 0.4 volts should show on
voltmeter.
Engine starter - Testing (B.80.A.82 - G.40.A.20)
Test Point
N°
1 Ignition Switch in "START" position.
Measure for 24 volts at B+ terminal
of 24 V Starter.
2 Measure for 12 volts at 24 V Battery
Switch (pin1).
3 Measure for 12 volts at 24 Start Re-
lay (pin 31A).
POWER PRODUCTION - STARTING SYSTEM
Expected Result
12 volts
If good reading, go to next test point.
12 volts
If good reading, go to test point 4.
12 volts
If good reading, repair open in circuit
804 (WH).
Less than 1 ohm
If good reading, go to next test point.
Less than 1 ohm
If good reading, go to next test point.
If less than 0.4 volts shown, and 12
Starter does not operate, replace 12
V Starter.
Expected Result
24 volts
If good reading, go to test point 6.
12 volts
If good reading, go to next test point.
12 volts
If good reading, go to next test point.
2 4/7/2006
B.80.A / 4
Other Result (Possible Cause)
Open circuit between 12 V Starter B+
terminal and 12 V System Batteries
positive terminal.
Caution: When performing continu-
ity test on this circuit, ensure that the
cable is disconnected from the bat-
tery positive terminal. Failure to do
so can result in damage to the test
meter.
Open circuit 804 (WH) between Start
Relay (pin 87) and 12 V Starter
(S terminal).
Go to next test point.
Open circuit 801 (RD) between 12 V
System Batteries and Start Relay.
Perform E -12 V Start Relay Test.
Check contact surface of 12 VStarter
with engine. Ensure 12 V Starter
is mounted securely. Check ground
strap between engine and chassis.
Open circuit between 12 V System
Batteries or 12 V Battery Switch and
ground.
12 V Battery Switch.
More than 0.4 voltsshowing on
voltmeter, replace cable between
battery positive terminal and 12 V
Starter B+ terminal.
Other Result (Possible Cause)
Open circuit between 24 V Starter B+
terminal and 24 V System Batteries
positive terminal.
Caution: When performing continu-
ity test on this circuit, ensure that the
cable is disconnected from the bat-
tery positive terminal. Failure to do
so can result in damage to the test
meter.
Go to next test point.
Open circuit between 24 V System
Batteries and 24 V Battery Switch
(pin2).
24 V Start Relay.
24 V Battery Switch.
Open circuit between 24 V Start Re-
lay (pin 31A) and 24 V System Bat-
teries positive terminal 24 V Start
Relay. V