New Holland CX720 Repair Manual page 3019

BODY AND STRUCTURE - ENVIRONMENT CONTROL Heating system
N° Test Point
5 Measure for 12 volts at Separator
Blower Relay (pin 1).
6 Measure for 12 volts at HVAC Con-
trol Module connector X128 (pin C4).
7 Ignition in "OFF" position.
Check for chassis ground at Separa-
tor Blower Relay (pin 2).
8 Ignition in "OFF" position.
Measure resistance from Separa-
tor Blower connector X144, circuit
933(BK) to ground.
Ventilation system Circulation fan - Testing (E.40.B.60.10 -
G.40.A.20)
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.
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 Ignition in "IGN" position.
blower speed to "HIGH" speed posi-
tion.
2 Measure for 12 volts at Main Blower
connector X156.
3 Measure for 12 volts at Main Blower
Relay Low (pin 5).
Expected Result
12 volts.
If good reading, go to test point 7.
12 volts.
If good reading, repair open circuit
902 (WH) between HVAC Control
Module connector X128 (pin C4)
and Separator Blower Relay (pin 1).
Less than 1 ohm.
If good reading, faulty Separator
blower relay.
Go to next test point.
Less than 1 ohm.
If good reading, replace Separator
Blower.
CAUTION
WARNING
Expected Result
Main Blower operates at high speed.
Adjust
If Main Blower runs at high speed, go
to test point 9.
12 volts.
If good reading, go to test point 8.
12 volts.
If good reading, repair short to
ground or open circuit 946 (WH) be-
tween Main Blower connector X156
and Main Blower Relay Low (pin 5).
Check in-line connector X006 (pin
G) for connection.
2 4/7/2006
E.40.B / 39
Other Result (Possible Cause)
Open or short to ground in circuit 902
(WH) between Separator Blower
Relay 1 and HVAC Control Module
connector X128 (pin C4).
connection at in-line connector X003
(pin 5).
Go to next test point.
HVAC Control Module.
Open circuit 944 (BK) between Sep-
arator Blower Relay (pin 2) and
ground.
Go to next test point.
Open circuit 933 (BK) between Sep-
arator Blower connector X144 and
ground.
Other Result (Possible Cause)
Main Blower
Main Blower Relay Low
Fuse #18
Go to next test point.
Main Blower
Main Blower Relay Low
Fuse #18
Open or short circuit.
Go to next test point.
Main Blower Relay Low
Open control circuit from HVAC Con-
trol Module.
Main Blower.
Go to next test point.
Check