2002 HONDA CIVIC heater

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 Gonditioning
Component Location Index
SERVICE VALVE{LOW.PRESSUBE SIDEI
EVAPORATOR CORE(Built-in the heater unit)Beplacement, page 21 42
COMPRESSORBeplacement, page 21 47Clutch Check, page 21-48Clutch Overhaul, page 21-49Thermal Protector Check, page 21-48Thermal Protector Replacement, page 21 51Relief Valve Replacement, page 21 51
SERVICE VALVE{HIGH-PRESSURE SIDEI
RECEIVER/DRYER
CONOENSEBReplacement, page 21-52

HEATER UNIT/COREBeplacement, page 21-43
BLOWEN UNITRemoval and Installation, page 21-39
HEATER VALVE CABLEAdjustment, page 21-46
BLOWER UNIT COMPONENTSReplacement, page 21-41
DUSTAND POLLENFILTERReplacement, page 21'39
RECIRCULATION CONTROL MOTORTest, page 21-36Replacement, page 21-36
MODE CONTROL MOTORTest, page 21-35Replacement, page 21-35
AIR MIX CONTROL MOTORTest, page 21'34Replacement, page 21'34
POWER TRANSISTORTest, page 21-38
HEATER CONTROL PANELRemovaland Installation, page 21 38
PUSH SWITCH ASSEMBLYRemoval and Installation, page 21'38EVAPORATOR TEMPERATURESENSORReplacement, page 21-37Test, page 21-37
21-5

Heating and Air Conditioning
General Troubleshooting Information
How to Retrieve a DTC
The heater control panel has a self-diagnosis function. To run the self-diagnosis function, do the following:
1. Turn the fan switch OFF.
2. Pressand holdthe recirculation control switch andthe rear window defoooer switch down.
3. Turn the ignition switch oN {lli.
4. Release both switches. The recirculation indicator and the rear window defogger indicator come on. The
recirculation indicator goes off 3 seconds later and the Ay'C indicator comes on. then the self-diagnosis will begin.
About 10 seconds later, the self-diagnosis will finish and the A,/C indicator goes off.
.lfanytroubleisfound.therecirculationindicatorblinksthediagnostictroublecode(DTC)toindicateafaulty
circuil or comDonent.. lf the system is OK, the recirculation indicator stays off.
atc
@r
RECIRCULATIONCONTROL SWITCH
BECIRCULATIONINDICATOB
/A\
-:@
INOICATOR
REAR WINDOWOEFOGGER INDICATOR
REAR WINDOWDEFOGGER SWITCH
Examole of DTC indication Pattern IDTC 7)
DTC 7
Reseiting the Selt-diagnosis Function
Turn the ignition switch OFF to cancel the self-diagnosis function. After completing repair work, run the self-diagnosis
function aoain to make sure thatthere are no other malfunctions.
Recirculation +indicatot
Recirculation +indicalorgo6s oft----->
21-8

DTC Troubleshooting Index
In case of multiple problems, the recirculation indicator will indicate only the DTC with the least number of blinks.
ln case of an intermittent failure, the heater control panel will store the DTC until the ignition is turned off.
DTC {Recirculation
Indication Blinks)
Detection ltemPage
7An open in the air mix control motor circuit(see paqe 21-16)
8A short ln the air mix control motor circuit(see Daoe 21-'16)
9A problem in the air mix control linkaqe, door, or motor(see paqe 21- 17)
10An open or shon in the mode control motor circuit(see oaqe 21-18)
11A problem in the mode control linkage, doors, or motor(see paqe 21191
12A problem in the blower motor circuit(see paqe 21-20)
13A problem in the EEPROM in the heater control panel;
the control oanel must be reolaced
(see page 21-38)
14An ooen in the evaDorator temDerature sensor circuit(see paqe 21-23)
A short in the evaDoralor temoerature sensor circuit(see oaqe 21-241
21-9

Heating and Air Conditioning
{
a
a
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
!

System Description
Heater Control Panel Inputs and Outputs
CONNECTOR A {r/rP)
CONNECTOR
CONNECTOR
HEATER CONTFOL PANEL CONNECIORS
CONNECTOR B (22P)
W re s de oitema eterm nals
Cavity Wire color_| \ln YAIR MIX POTENTIAL +5V
Sional
OUTPUT2LT GRNSENSOR COMMON GROUNDINPUT3PNK/BLUAIR MIX HOTOUTPUTBLUA,/C PRESSURE SWITCHINPUT5GRNA/ELRECIRCULATEINPUT6GRNA/VHTFRESHINPUT7BLUI/ELPOWER TRANSISTOROUTPUT8BLU/REDBLOWER FEEDBACKINPUTIGRNAIR MIX COOLOUTPUT10YEL/REDMODE DEFOUTPUT11. YEVBTU
YEL/BLK
MODE VENT
REAR WINDOW DEFOGGER RELAY
OUTPUT
INPUTBLKGROUNDOUTPUT14B LK/YELlG2 (Power)INPUT
Bon
CavityWire colorSiqnal1--T
2
3BLIVREDREAR WINDOW DEFOGGER SWITCH LEDINPUT
4LT GRNA./C SWITCH LEDINPUT
5LT GRN/BLKRECIRCULATION CONTROL SWITCH LEDINPUT
6PNVBLKAIR MIX POTENTIALOUTPUT
7BRNEVAPORATOR TEIMPERATURE SENSOROUTPUT
8
9
10
GAUGE ASSEMBLYal' 'TDr ri11RED
RED/BLKTAILLIGHTS RELAYINPUT
14BLUREAR WINDOW DEFOGGER SWITCHINPUTicLT GRN/REDA/C SWITCHINPUT16YEVREDRECIRCULATION CONTROL SWITCHINPUT17YEUGRNMODE 4OUTPUT18WHT/BLUMODE 3OUTPUT19RED/BLUMODE 2OUTPUT20RED/YELMODE 1OUTPUTBRN^,^/HTIGN (PowedOUTPUT22R E DA/r'HT(Not used)
(cont'd)
21-11

Heating and Air Conditioning
DTC Troubleshooting
DTC 7: An Open in the Air Mix Control Motor
Circuit
1. Test the air mix control motor {see page 2'l-341.
ls the air mix control motor OK?
YES-Go to step 2.
NO-Replace the air mix control motor.l
2. Disconnect the air mix control motor 5P connector.
3. Disconnect heater control panel connectors A {14P)
and B (22P).
4. Check for continuity between the following
terminals of heater control panel connectors A
(14P) and B (22P) and the air mix control motor 5P
connector,
14P: 5P:
No. 1 No.5
No.2 No.4
No.3 No.2
No.9 No. 1
22P: 5P:
No.6 No.3
Wire side ol lem.letehi.6ls
ls there continuity?
YES-Check for loose wires or poor connections at
heater control oanel connectors A (14P) and B (22P)
and at the air mix control motor 5P connector. lf the
connections are good. substitute a known-good air
mix control motor, and recheck, lf the symptom/
indication goes away, replace the original air mix
control motor. lf the symptom/indication continues,
substitute a known-good heater control panel, and
recheck. lf the symptom/indication goes away,
replace the original heater control panel.l
NO Repair any open inthewire(s) ketweenthe
heater control panel and the air mix control
motor.l
21-16
DTC 8: A Short in the Air Mix Control Motor
Circuit
1. Test the air mix control motor(see page 21-341.
ls the ait mix control motor OK?
YES-Go to step 2.
NO-Replace the air mix contorol motor.I
2. Disconnect the air mix control motor 5P connector.
3. Disconnect heater control panel connectors A (14P)
and B (22P).
4. Check for continuity between body ground and
heater control panel connector A (14P) terminals
No. 1, 2, 3, and 9 individually, and between body
ground and heater control panel connector B (22P)
terminal No. 6.
HEATERCONTROL PANEL CONNECTOR A {I4PI
HEATER CONTFOL PANELCONNECTOR B I22P1
ls therc continuity?
YES-Repair any shortto body ground ln the
wire(s) between the heater control panel and the air
mix control motor.l
NO-Go to step 5.
Wire side of female terminals
Wire side oilema e lerminals