2003 HONDA CIVIC 21-29

21-2
z t-'5
z t-o
z t-o
21-8
21-9
21-10
21-11
21-14
z t- to
HVAC (Heating, Ventilation, and Air Gonditioningl
Heating and Air Conditioning
SpecialTools
Comoonent Location lndex ........
A/C Service Tios and
Precautions
A,/C Refrigerant Oil
ReDlacement
General Troubleshooting
lnformation
DTC Troubleshooting Index .......
Symptom Troubleshooting
1ndex..............
System Description .....................
Circuit Diagram
DTC Troubleshooting ..................
Recirculation Control Motor
CircuitTroubleshooting .......... 21-25
Heater Control Power and Ground
Circuits Troubleshooting ........ 21-27
Condenser Fan Circuit
Troubleshooting ...................... 21-28
Radiator and Condenser Fans
Common Circuit
Troubfeshooting ...................... 21-29
Compressor Clutch Circuit
Troubleshooting ...................... 21-30
A,/C Pressure Switch Circuit
Troubleshooting ...................... 21-32
Air Mix Control Motor
Test and Reolacement ............. 21-34
Mode Control Motor
Test and Replacement ............. 21-35
Recirculation Control Motor
Test and Reolacement ............. 21-36
Evaporator Temperature Sensor
Reolacement and Test ............. 21-31
Power Transistor Test ................. 21 -38
Heater Control Panel and
Push Switch Assemblv
Removal and Installation ........ 21-38
Dust and Pollen Filter
Reolacement ..21-39
Blower Unit Removal and
lnstallation ...... 21-39
Blower Unit Comoonents
ReDlacement ............................ 21-41
Evaporator Core
Reolacement ..21-42*Heater Unit/Core
ReDlacement ..21-43
Heater Valve Cable
Adjustment .....21-46
CompressorReplacement .......... 21-47
Comoressor Clutch Check .......... 21-48
Comoressor Clutch Overhaul ..... 21-49
Compressor Thermal Protector
Reo1acement ............................ 21-51
Comoressor Relief Valve
Reolacement ............................ 21-51
Condenser Reolacement ............ 21-52
Refrigerant Recovery .................. 21-53
System Evacuation ...................... 21-54
System CharginS ......................... 21-55
Refrigerant LeakTest .................. 21-56
A,/C Svstem Tests ........................ 21-57

Heating and Air Conditioning
{
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SvmptomDiagnostic procedureAlso check for
Recirculation control doors do not
change between Fresh and Recirculate
Recirculation Control Motor
Circuit Troubleshooting (see page
21 251
Cleanliness and tightness of all
connectors
Both heater and Ay'C do not workHeater Control Power and Ground
Circuits Troubleshooting (see
page 21-27)
Blown fuse No. '14 (10A) in the
under-dash fuse/relay box
Poor ground at G501
Cleanliness and tightness of all
conneclors
Condenser fan does not run at all (but
radiator fan runs with the Ay'C on)
Condenser Fan Circuit
Troubleshooting {see page 21-28)
. Poor ground at G301. Cleanliness and tightness of all
connectors
Both fans do not run with the A,/C onRadiator and Condenser Fans
Common Circuit Troubleshooting
(see page 21-29)
Blown fuse No. 1 (20A) and No.4
(20A) in the under-hood fuse/relay
box
Poor ground at G30l
Cleanliness and tightness of all
connectors
Compressor clutch does not engage(both fans run with A,/C on)
Compressor Clutch Circuit
Troubleshootinq (see Daqe 21-30)
Cleanliness and tightness of all
connectors
A/C system does not come on (both
fans and compressor)
Ay'C Pressure Switch Circuit
Troubleshooting (see page 21-32)
Blown fuse No. 1 (20A) and No. 4
(20A) in the under-hood fuse/relay
box
Poor ground at G301
Cleanliness and tightness of all
connectors
\Symptom Troubleshooting Index
\
21-10
!

Heating and Air Conditioning
Condenser Fan Circuit Troubleshooting
NOTE: lf neither the condenser fan nor the radiator fan
work, go to Radiator and Condenser Fans Common
Circuit Troubleshooting (see page 21-29).
1. Check the No. 1 (20A) fuse in the under-hood
fuse/relay box, and the No. 14 (10A)fuse in the
under-dash f use/relay box.
Are the tuses OK?
YES-Go to step 2.
NO Replace the fuse(s), and recheck. t
2. Remove the condenser fan relay from the
under-hood fuse/relay box, and test it(see page 22-51).
ls the relay OK?
YES Go to step 3.
NO- Replace the condenser fan relay.l
3. Measure the voltage between the No, 2 terminal of
the condenser fan relay 4P socket and body ground.
CONDENSER FAN RELAY ilP SOCKET
ls thete battery voltage?
YES-Go to step 4.
NO-Replace the under-hood fuse/relay box.l
21-28
4. Connect the No. landNo.2terminalsof the
condenser fan relay 4P socket with a jumper wire.
CONDENSER FAN RELAY itP SOCKET
JUMPER WIRE
Does the condenser lan tun?
YES-Go to step 5.
NO Go to step 8.
5. Disconnect the jumper wire.
6. Turn the ignition switch ON (ll).
7. Measure the voltage between the No, 3 terminal of
the condenser fan relay 4P socket and body ground.
ls there battery voltage?
YES Replace the under-hood fuse/relay box.t
NO-Repair open in the wire between the No. 14
fuse in the under-dash fuse/relay box and the
condenser fan relay.l
Disconnect the jumper wire.
CONDENSER FAN FELAY 4P SOCKET
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9.
10.
Disconnect the condenser fan 2P connector,
Check for continuity between the No. 1 terminal of
the condenser fan relay 4P socket and the No. 2
terminal of the condenser fan 2P connector.
CONDENSER FAN RELAY 4P SOCKET
CONDENSER FAN 2P CONNECTORWire side of female terminals
Is there continuity?
YES Go to step 1 1.
NO- Repair open in the wire between the
condenser fan relay and the condenser fan,I
Check for continuity between the No. 1 terminal of
the condenser fan 2P connector and body ground.
CONDENSER FAN 2P CONNECTOR
12
BLK
o
Wire side of {emale terminals
ls there continuity?
YES- Replace the condenser fan motor.I
NO Check for an open in the wire between the
condenser fan and body ground. lf the wire is oK,
check for poor ground at G301.1
'11 .
Radiator and Condenser Fans
Common Circuit Troubleshooting
NOTE; lf both fans and the Ay'C compressor clutch do
not work when the Ay'C switch is on, go to Ay'C Pressure
Switch Circuit Troubleshooting (see page 21-32l, .
1. Check the No. 1 {20A} and No. 4 (20A) fuses in the
under-hood fuse/relay box, and the No. 14 (10A)
fuse in the under-dash fuse/relay box.
Are the tuses OK?
YES Go to steD 2.
NO Replace the fuse(s), and recheck.l
2. Remove the condenser fan relav from the
under-hood f use/relay box.
3. Turn the ignition switch ON (ll;.
4. Measure the voltage between the No. 3 terminal of
the condenser fan relay 4P socket and body ground.
ls there battery voltage?
YES Go to step 5.
NO Repair open in the wire between the No. 14
fuse in the under-dash fuse/relay box and the
radiator fan relay, and the condenser fan relay.l
5. Turn the ignition switch OFF.
6. Reinstall the condenser fan relay.
7. Make sure the IVC switch is OFF.
8. Turn the ignition switch ON (ll).
(cont'd)
CONDENSER FAN RELAY 4P SOCKET
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21-29