thermostat HONDA CIVIC 1998 6.G User Guide

Heater Control Panel Input/Output Signals
HEATER CONTROL PANEL lilP CONNECToR
Wire side of lemale terminals
21-7
Terminal
No.
Wire
colorSignalTerminal
No.
Wire
colorSignal
1YELHEAT/DEFINPUT8YEVREDVENTINPUT
BLfiELINPUT9G RNI/ELHEATIr'ENTINPUT
WHT/BLU+BINPUT'10BLKGROUNDOUTPUT
4YEUBLUDEFINPUT11*BLU/REDA./C THERMOSTATINPUT
5REDDASH LIGHTS
BRIGHTNESS CONTROLLEROUTPUT12GRN/WHTFRESHINPUT
6RE D/8LKCOMBINATION LIGHT
SWITCHINPUT13GRN/REDRECIRCULATEINPUT
1BLUMHTHEATINPUT14GRNHEATER FAN SWITCHOUTPUT

Troubleshooting -'99 - 00 Models
Heater Control Panel Input/Output Signals
HEATER CONTROL PANEL CONNECTORS
8P CONNECTOR2OP CONNECTOR12P CONNECTOR
Wire side of female terminals
8P CONNECTOR (O qn Circuit Diagram)
20P CONNECTOR {D on circuit Diagram}
*: with Ay'c
12P CONNECTOR (tr on Circuit Diagraml
CavityWire colorSignalCavilyWhe colorSignal
BLU/8LKBLOWER FEEDBACKINPUT5REDDASH LIGHTS BRIGHTNESSCONTROLLEROUTPUT
2GRN/lVHTFRESHINPUT6BLKGBOU N DOUTPUT
3GRN/REDRECIRCULATEINPUT7BLU/YELREAR WINDOW DEFOGGERRELAYOUTPUT
4RED/BLKCOMBINATION LIGHT SWITCH(Via No. 30 (7.5 A) fuse)INPUT88LfiELlG2 {Power)INPUT
CavityWire colorSignalCavityWire colorSignal
LTGRN/BLKPOWER TRANSISTOR EASEOUTPUT't1BLU/REDAy'C THERMOSTATINPUT
2BRNMHTMODE CONTROL MOTORGROUNDINPUT12BRNAIR MIX CONTROL MOTORGROU NDINPUT
3RE D/YELAIR MIX HOTOUTPUT13ORNAA/HTBLOWER MOTOR HIGHRELAYINPUT
RED,ryvHIAIR MIX COOLOUTPUT14
5YEUBLUMODE DEFINPUTPN K,/BLKAIR MIX POTENTIALOUTPUT
6YEUREDMODE VENTINPUT16
7GRNI/ELMODE HEAT/r'ENTINPUT11
IBLUAVHTMODE HEATINPUT18
9YELMODE HEAT/DEFINPUT19
10WHT/BLU+B (Power)INPUT20GRYAIR MIX POTENTIAL +5 VOUTPUT
CavityWilecolorSignalCavityWi.e cololSignal
lSWITCH LED COMMONOUTPUT1SWITCH LIGHTS +OUTPUT
2ISWITCH LIGHTS -INPUT
39SWITCH COMMONINPUT
4RECIRCULATION CONTROLSWITCH LEDINPUT10A,/C SWITCHOUTPUT
5A./C SWITCH LEDINPUT11RECIRCULATION CONTROLSWITCHOUTPUT
6REAR WINDOW DEFOGGERSWITCH LEDINPUT12REAR WINDOW DEFOGGEBSWITCHOUTPUT
21-36

Air Conditioning
Speciaf Tools ......'.....' 22-2
f f f ustrated f ndex ......................... ".......' 22-3
Wiring/Connector Locations'.........'.... 22'4
Description
Outfine ............ .......22-s
Circuit Diagram
'96 - 98 Models ......"..........".......'.... 22-6
'99 Modef """""""' 22-7
Troubleshooting
Symptom Chart ".'......""................. 22-8
Flowcharts
Condenser Fan .........".................,..'. 22-9
Compressor .....""" 22-12
A/C System .........'.22'17
A/C Thermostat
Test ........'.......' """'22'21
Relays
Test ....."'......... ..""'22-21
A/C Service Tips and Precautions ......22-22
A/C System Torque Specifications '...22-23
A/C System Service
Performance Test ... '."......... ".... ....'..22-24
Pressure Test Chart .................. .... "' 22-26
Recovery ...".........," 22-27
Evaporator
Replacement .....",' 22'24
Overhauf .....-.....""' 22'29
Compressor {SANDEN}
Repf acement ......'.' 22-30
fffustrated fndex ......"..................'.... 22'32
Cf utch Inspection ......... "............ ...... 22-33
Clutch Overhau I ........................ ....... 22-34
Thermal Protector Replacement .... 22-36
Relief Valve Replacement ......'..."". 22-36
Compressor (DENSO)
Repfacement ..""',' 22-37
lf lustrated Index ............................... 22-39
Clutch lnspection ............."'...... "'.... 22-40
Cf utch Overhaul .....................'......... 22-41
Ref ief Valve Replacement'..'......"'.. 22-42
A/C Compressor Belt
Adiustment ............22'43
Condenser
Repfacement .......,,22'44
A/C System Service
Evacuation ...,,,.......22-45
Charging '..........--'..22'46
Leak rest """""""'22-46

lllustrated Index
A/C PRESSURE SWITCHWhen the refrigerant pressure is below 200 kPa {2 0 kg7cm',
28 psi) due to ;frigerant leakage or above 3200 kPa (32 kgf/cm''
455 psi) due to refrigerant blockage, the lVC pressure swrtch
SERVICE VALVE
{LOW.PRESSURE SIDE)
EVAPORATORReplacement, page 22-28
Overhaul, page 22 29
Beplacement, Page 22'44
opens lhe circuit to ihe AVC switch and stops the air condilioning
to protect the comPressor'
RECEIVER/DRYER
COMPRESSORSANDENIReplacement, Page 22 30
CIutch Inspection, Page 22 33
Thermal Protector Inspection, page 22 33
Clutch Overhaul, Page 22'34
Thermal Protector Replacement, page 22 36
Refief Vafve Replacemenl, page 22'36
DENSO:Replacement, Page 22-37
Clutch Inspection, Page 22-40
Clutch Overhaul, Page 22_41
Relief Valve Replacement, page 22-42
A/C THERMOSTATTest, page 22 21
22-3

Description
Outline
The air conditioner system removes heat from the passenger compartment by circulating refrigerant through the system
as shown below.
BLOWER FAN
EVAPORATOR(Absorption of heati
EOUALIZING TUBE(Meters pressure andimproves the expansionvalve reaction time)
into the evaporator)CAPILLATY TUBE SENSING BULB
lControls the temPerature of the
ref rigerant leaving the evaporator
by metering the expansion valve)
/\
THERMOSTAT
A/C PRESSURE SWITCH
When the refrigerant is below
200 kPa (2.0 kgtcm',28 Psi)or above 3,200 kPa 132 kgflcm',
455 psi), the Ay'C pressure
switch opens the circuit to
the A,/C switch and stops the
EXPANSION VALVE(Meters the requiredamount of refrigerant
airconditioning to Protect the
compressor.
RECEIVER/DRYER(Traps debris, andremoves morsturel
THERMAL PROTECTOR
{Opens the comPressorclutch circuit when the
compressor temPeraturebecomes too high)
RELIEF VALVE(Relieves pressure at the
compressor when thepressure is too high)
(Radiation of heat)
I
f-r--; I
(Suction and comPression,
HIGH PRESSURE VAPOR
HtGH PRESSUBE LIOUID
LOW PRESSURE LIOUID
This car uses HFC-134a (R-134a) refrigerant which does not contain chlorofluorocarbons Pay attention to the following
service items:
. Do not mix refrigerants CFC-12 (R-12) and HFC-134a (R-134a)' They are not compatible'
. Useonlythe recommended polyalkyieneglycol (PAG) refrigerant oil designedforthe R-134a compressor (SANDEN: SP-
10; DENSO: ND_OIL8). Intermixing ihe re-commended (pAG) refrigerant oil with any other refrigerant oil will result in
compressor failure.
. All A,,ic system parts {compressor, discharge line, suction line, evaporator, condenser, receiver/dryer, expansion valve'
O-rings for joints) have to be proper for refrigerant R- 134a Do not confuse with R-l2 parts'
. Use a halogen gas leak detector designed for refrigerant R-134a
. R-12 and R-134a refrigerant servacing equipment are not interchangeable. Use only a recovery/recycling/charging station
that is u,L.-listed and is certified to meet the requirements of sAE J2210 to service R-134a air conditioning systems'
. Always recover the refrigerant R-134a with an approved recovery/recycling/charging station before disconnecting any
A,/C fitting.
S]
22-5

Troubleshooting
A/C System (cont'd)
From page 22-11
. _Ff,, __
I11213[
,r,il*"-T",-.r-'..owrRE I
To page 22-19 1'96 - 98 models)
A/C THERMOSTAT 3P CONNECTOR
Wire side oI female terminals
Check tor an open in the wire:1. Turn the ignition switch OFF.2. Disconnect the A/C thermostat 3P connector.3. Turn the ignition switch ON (ll).
4. Measure the voltage betweenthe No. 3 terminal of the Ay'Cthermostat 3P connector andbody ground.
Repai. open in the wire betweentho No. 17 tuso and the A/C the.-mostat.
Check loi an open in the wi.e:Measure the voltage between theNo. 1 terminal of the A,/C thermostat 3P connector and bodyground,
Ropair open in the wire betwoenthe condedlo. lan rolay and theA/C thormostat.
ls there battery voltage?
Check the A/C th6rmostat:1. Turn the ignition switch OFF.2. Reconnect the A,/C thermostat3P connector.3. Connect the No. 2 terminal toground with a iumperwire.4. Start the engine.
Do the fan run and the com-pressor clutch engage?
To page 22-20 ('99 - 00 models)
22-18

Troubleshooting
('99 00 models)
From page 22 18
Check lor an open in the wire:1. Turn the ignition switch OFF,then disconnect the ju mper
2. Disconnect the heater controlpanel 20P connector.3. Turn the ;gnition switch ON{

i.4. Measure the voltage betweenthe No. 11 terminal of theheater control panel 20P con-nector and body ground.
Ropai. opan in tho wira batwaonthe A/C thermostat and thehoater control oanol.ls there battery voltage?
Check the push switch:1. Turn the ignition switch OFF.2. Disconnect the push switch12P connector.3. Check for continuity betweenthe No. I and No. 10 terminalsof the push switch 12P con-nector with the A/C switch ON.
Check for loose wi.es or poor
connections el the hgater controlpanel 20P connector and pushswitch 12P connector and at theA/C thermostat 3P connector. Ittha connections are good, substi-tute a known-good heatea con-trol pan€|, and recheck. lf thesymptom/indication goe3 away,replace lhe original healer con-trol oan€|,
HEATER CONTROL PANEL anP CONNECTOR
Wire side of temale terminals
PUSH SW]TCH 12P CONNECTOR
Wire side of female terminals
,/1,/156
7819t01112
I
I
I

A/C ThermostatRelays
Test
1.Remove the Ay'C thermostat (see page 22-29).
Connect baftery power to the No. 3 terminal, ground
the No. 2 terminal, and connect a test light between
the No. 1 and No. 3 terminals.
NOTEr Use a 12 V,3 W- l8 W test light.
Dip the IVC thermostat into a cup filled with ice water,
and check the test light.
Serp6ntine-type evaporator
The light should go off at 36 - 39'F {2 - 4"C} or less, and
should come on at 39 - 41"F (4 - 5"C) or more
Laminale-type evaporator
The light should go off at 39 - 43'F (4 - 6'C) or less, and
should come on at 43 - 45"F (6 - 7'C) or more
lf the light doesn't come on and go off as specified,
replace the PVC thermostat.
12V,3W-18W
Test
There should be continuity between the No, 1 and No.2
terminals when power and ground are connected to the
No.3 and No. 4 terminals, and there should be no conti-
nuitv when Dower is disconnected.
2
Condenser fan relay
Compressor clutch relay
a
a
,I Ib
In Io'r I
t\----,'
t:n
,,l[4..-.
22-21

A/C System Service
Pressure Test Chart
NOTE: Performance Test is on page 22-24,
Test resultsRelated symptomsProbabl€ causeRemedy
Discharge (high)
pressure aDnor-
mally high
After stopping compressor. pres-
sure drops to about 200 kPa
{2.0 kgflcm,,28 psi) quickly, and
then falls gradually.
Air in systemRecover, evacuate, and
recharge with specified amount.
Evacuation: see page 22-45
Charging: see page 22-46
Reduced or no air flow through
condenser
. Clogged condenser fins. Condenser fan not work-
ing properly
Clean.
Check voltage and fan rpm.
Check fan direction.
Line to condenser is excessively
hot.
Restricted flow of refriger-
ant in system
Restricted lines
Discharge pres-
sure abnormally
High and low pressures are bal-
anced soon after stopping compres-
sor, Low side is higher than normal.
. Faulty compressor dis-
charge valve. Faulty compressor seal
Replace the compressor.
Outlet of expansion valve is not
frosted, low pressure gauge indi-
cales vacuum.
. Faulty expansion valve. Moisture in system
. Replace,. Recover, evacuate, and
recharge with specified
amount.
Suction (low)
pressure abnor-
mally low
Expansion valve is not frosted, and
low oressure line is not cold. Low
pressure gauge indicates vacuum.
. Frozen expansion valve. Faulty expansion valve
ReDlace the exoansion valve.
Discharge temperature is low. and
the air flow from vents is restricted.
Frozen evaporatorRun the fan with compressor
off. then check A,/C thermostat.
Exoansion valve is frosted.Clogged expansion valveClean or replace.
Receiver/dryer outlet is cool, and
inlet is warm (should be warm
during operation).
Clogged receiver/dryerReplace.
Suction pres-
sure abnormally
hig h
Low pressure hose and check
joint are cooler than the tempera-
ture around evaporator.
. Expansion valve open too
long. Loose expansion capillary
tube
Repair or replace.
Suction oressure is lowered when
condenser is cooled bv water.
Excessive refrigerant in sys-
tem
Recover. evacuate, and
recharge with specified amount.
High and low pressure are equal-
ized as soon as the compressor is
stopped, and both gauges fluctu-
ate while running.
Faulty gasket
Faulty high pressure valve
Foreign particle stuck in
high pressure valve
Replace the compressor.
Suction and dis-
charge pres-
sures abnormally
h igh
Reduced air flow through con-
denser.
. Clogged condenser fins. Condenser fan not work-
ing properly
Clean condenser.
Check voltage and fan rpm.
Check fan direction.
Suction and dis-
charge pressure
abnormally low
Low pressure hose and metal end
areas are cooler than evaporator.
Clogged or kinked low pres-
sure hose parts
Repair or replace.
Temperature around expansion
valve is too low compared with
that around receiver/dryer.
Clogged high pressure lineRepair or replace.
Refrigerant leaksCompressor clutch is diny,Compressor shaft seal leakingReplace the compressor.
Compressor bolt{s) are diny.Leaking around bolt(s)Tighten bolt(s) or replace com-
pressor.
Compressor gasket is wet with oil.Gasket leakingReplace the compressor.
22-26

Evaporator
1.
Replacement
4.
Move the temperature control to "HOl"
'96-98: Slide the temoerature control lever.'99-00: Turn the ignition switch ON (ll), then turn
the temperature contol knob. Turn the ignition
switch off.
Remove the battsry.
Rgcover the refrigerant with a rocovery/recycling/
charging station (see page 22-271.
Remove the bolts, then disconnect th6 suction 8nd
receiver lines from th6 evaoorator.
NOTE: Plug or cap the lines imm€diatoly after dis-
connecting them to avoid moisture and dust con-
tamination.
6xl.0mm9.8 n*ln ll.0 tg6m.7.2 lbt frl
RECEiVER UNE
Remove the glov6 box (see section 20).
Removo the self-tapping scr€w and the passeng€r's
dashboard lower cover. Removs the bolt. the nut
8nd the kn€e bolst6r, th6n r6mov6 th6 fiv6 bolts and
the glove box frame.
6.
srrcrrc u E
22-28
7. Disconnect the connector from th€ Ay'C thermostat,
and r€movs the wire harness from the ovaporator.
Remov6 tho four self-tapping screws, tho mounting
bolt and ths mounting nut. Disconnect th€ drain
hose, then remov€ th6 avagorator.
6 x l.0.nm9.8 l$m lt.o ldm, 7.2 bl.tt)
Install in the reverse order of removal. Make note of
th€ following items.
o lf you'r6 installing a new evaporator, add rofriger-
ANt OiI {SANDEN, SP-10 Or DENSO, ND-OIL 8)
lsas page 22-221.
. Replace the O-rings with now ones 8t 68ch titting,
and apply 8 thin coat of r€frlgersd oil before
installing them.
NOTE: Be sure to use the right O-rings for HFC-
134a (R-134a) to avoid loakago.
. Apply s€alant to tha grommets.
. Mske sure that ther€ is no air leakage.
. Chargs ths system {s€€ page 22-161, and tost its
performance (see pags 22-211.