New Holland CX720 Repair Manual page 1334

Head light Relay - Testing (A.40.A.11.82 - G.40.A.20)
N° Test Point
1 Turn Road Light Switch to "High
Beam" position.
Measure for 12 volts at High Beam
Relay (pin 5).
2 Turn Road Light Switch to "High
Beam" position.
Measure for 12 volts at High Beam
Relay (pin 1).
3 Measure for 12 volts at High Beam
Relay (pin 3).
4 Disconnect the High Beam Relay.
Measure resistance on circuit 192
(BK) between High Beam Relay (pin
2) and ground.
Head light Switch - Testing (A.40.A.11.83 - G.40.A.20)
NOTE: The batteries must be fully charged and all connections clean and tight. Use a multimeter (DVOM) or an
unpowered test light for these tests.
DO NOT use a self-powered test light for any of these tests. Use of a self-powered light can cause damage
to components in this system. M979
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. M980
N° Test Point
1 Measure for 12 volts at Road Light
Switch connector X256 (pin 5).
2 Disconnect Road Light Switch.
Measure for 12 volts at Road Light
Switch connector X256 (pin 5).
3 Reconnect Road Light Switch.
Measure for 12 volts at Road Light
Switch connector (pin 8).
4 Disconnect Road Light Switch.
Measure for 12 volts at Road Light
Switch connector X256 (pin 8).
DISTRIBUTION SYSTEMS - LIGHTING SYSTEM
Expected Result
12 volts.
If good reading, relay is functioning
properly.
12 volts.
If good reading, go to next test point.
12 volts.
If good reading, go to next test point.
Less than 1 ohm.
If good reading, replace the High
Beam Relay.
CAUTION
WARNING
Expected Result
12 volts.
If good reading, go to test point 3.
12 volts.
If good reading, replace Road Light
Switch.
12 volts.
If good reading, go to test point 5.
12 volts.
If good reading, replace Road Light
Switch.
2 4/7/2006
A.40.A / 18
Other Result (Possible Cause)
High Beam Relay.
Adjacent circuits.
Go to next test point.
Open or short to ground in circuit
191 (YE) or 218 (YE) between High
Beam Relay (pin 1) and Road Light
Switch connector X256 (pin 4). A
short to ground will blow the Fuse
#51.
Road Light Switch.
Open circuit 185 (RD) between High
Beam Relay (pin 3) and Fuse #32.
Short to ground on circuit 186 (PU)
between High Beam Relay (pin 5)
and Low Beam Lamps connector
X169 (pin B).
A short to ground will blow the Fuse
#32.
Open in circuit 192 (BK) between
High Beam Relay (pin 2) and ground.
Other Result (Possible Cause)
Open or short to ground on cir-
cuit 213 (RD) between Road Light
Switch connector X256 (pin 5) and
Fuse #51.
Open or short to ground on cir-
cuit 213 (RD) between Road Light
Switch connector X256 (pin 5) and
Fuse #51.
Open or short to ground on cir-
cuit 214 (RD) between Road Light
Switch connector X256 (pin 8) and
Fuse #51.
Open or short to ground on cir-
cuit 214 (RD) between Road Light
Switch connector X256 (pin 5) and
Fuse #51.