New Holland CX720 Repair Manual page 1348

A.
Series 1206-1347
Wiring harness - Electrical schematic frame 36 (A.30.A.88-C.20.E.36)
Series 1348 and above
Wiring harness - Electrical schematic frame 38 (A.30.A.88-C.20.E.38)
Brake light Relay - Testing (A.40.A.14.82 - 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 Depress brake pedal.
Measure for 12 volts at Brake Lights
Relay (pin 5).
2 Depress brake pedal.
Measure for 12 volts at Brake Lights
Relay (pin 1).
3 Measure for 12 volts at Brake Lights
Relay (pin 3).
4 Disconnect the Brake Lights Relay.
Measure resistance on circuit 159
(BK) between Brake Lights Relay
(pin 2) and ground.
Brake light Indicator lamp - Testing (A.40.A.14.84 - G.40.A.20)
N° Test Point
1 Turn Road Light Switch to Marker
Lights position.
Measure for 12 volts at fuse F-34.
DISTRIBUTION SYSTEMS - LIGHTING SYSTEM
CAUTION
WARNING
Expected Result
12 volts.
If good reading, the relay is OK.
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, go to next test point.
Expected Result
12 volts.
If good reading, go to next test point.
2 4/7/2006
A.40.A / 32
Other Result (Possible Cause)
Brake Lights Relay.
Adjacent circuits.
Go to next test point.
Open or short to ground in circuit 183
(WH) between Brake Lights Relay
(pin 1) and CCM-2 connector X015
(pin J1-18).
See Service manual for testing of
CCM.
Open circuit 56 (RD) between Brake
Lights Relay (pin 3) and Fuse #52.
Short to ground on circuit 78 (PU)
between Brake Lights Relay (pin 5)
and Brake Lamps.
A short will cause Fuse #52 to blow.
Open circuit 159 (BK) between
Brake Lights Relay (pin 2) and
ground.
Other Result (Possible Cause)
Perform Road Light Switch Test.