air temp HONDA CIVIC 1999 6.G Repair Manual

Heater
lllustrated Index
'96 - 98 Models ................................ 21'2
'99 - 00 Models ................................ 21'3
Circuit Diagram
'96 - 98 Models .....21-4
'99 - 00 Models ................................ 21-5
Troubleshooting - '96 - 98 Models
Symptom Chart ............................... 21-6
Heater Control Panel Input/
Output Signals ..............,.............. 21-7
Flowcharts
Blower Motor Speed ................... 21-8
Bf ower Motor ,...21'10
Mode Control Motor ............... ,.'.' 21-13
Recirculation control Motor ....... 21-16
Heater Control Panel ................ ... 21 -14
Troubleshooting - '99 - 00 Models
Symptom Chart ............................... 21-19
Seff-diagnosis Function ............,,,.... 21-20
Flowcharts
Air Mix Control Motor ......,.......... 21-21
Mode Control Motor ............... ..... 21 -25
Recirculation Control Motor ....... 21-27
Bf ower Motor Speed .............. .....21'29
Bf ower Motor ....21-31
Heater Control Panel ................,.. 21-35
Heater Control Panel Input/
Output Signals ............................. 21-36
Blower Unit
Repf acement .........21-37
Overhaul ................ 21-38
* Heater Unit
Replacement ....'....21-39
overhaul """" """' 21-4'l
Heater Control Panel
Repfacement .........21'42
Overhaul -'96 - 98 Models ........... 21-43
Temperature Control
Adjustment - '96 - 98 Models """" 21-44
Adiustment - '99 - 00 Models .......21-45
Air Mix Control Motor
Test - '99 - 00 Models ...........' .......21'46
Replacement - '99 - 00 Models ....21'46
Mode Control Motol
Test ................, .,...'.21'47
Replacement '.'."...21-47
Recirculation Control Motor
Test ................. .......21-48
Repf acement ......." 21-48
Relays
Test ................. .......2'l-49
Heater Fan Switch
Test - '96 - 98 Models ............. .......21-49
Mode Control Switch
Test -'96 - 98 Models ..........."....... 21-50
Power Transistor
Test - '99 - 00 Models ....'........ ....".21-50
*: Read SRS Drecautions before working in this area.

lllustrated Index
'96 - 98 Models
SRS components are located in this area. Review the SRS component locations, precautions, and procedures in the SRS
section {24) before performing repairs or service.
BLOWER UNITReplacement, page 21-37Overhaul, page 21-38
HEATER UNITBeplacement, page 21-39Overhaul, page 21-41BLOWERRESISTOBTest,
CONTROL MOTORTest, page 21-48Replacement, page 21'48
a/c swtTcH{wirh A/c)
MOO€MOTORTest, page 21 47Replacement, page 21'47
AIR MIX CONTROL CABLEAdjustment, page 2'1-44Replacement, page 21'43
HEATER FANswtTcHTest, page 2l'49
MODEHEATER CONTBOLPANELswrTcHEsTest, page 21 50Rgplacement, page 2'l-42Overhaul, page 21-43
TEMPERATURE CONTROLLEVERAdiustment, page 21 44
Detroster-aqtivated A/C System
Turning the defroster on activates the A,/C and sets the air flow mode to FRESH. lt is possible to turn the A,/C off or to
change the air flow to RECIRCULATE by pressing the A/C bunon or the FRESH/RECIRCULATE button.
21-2

'99 - 00 Models
SRS components are located in this area, Review the SRS component locations, precautions, and procedures in the SRS
section (24) betore perfoming repairs or service.
HEATER UNITReplacement, page 21'39
Overhaul, page 21-41
BLOWEB UNITReplacement, page 21-37Overhaul, page 21 38
HEATER FANswtTcH
RECIRCULATIONCONTROL MOTORTest, page 21-48Beplacement, page 21-48
AIR MIX CONTROL MOTOBTest, page 21-46Replacement, page 21 46
BLOWERTest, page 21-49
POWER TRANSISTORTest, page 21 50
HIGH RELAY
MODE CONTROLDIALHEATER VALVE CABLEAdjustment, page 21 45TEMPERATURE CONTROLDIALAdjustment, page 21-45
REAR WINDOWDEFOGGERswtrcHSee section 23MODEMOTORTest, page 21 47Replacement, page 2 l-47A/C SWTTCH
lwith A/cl
CONTROL SWITCH
21-3

Blower Unit
Replacement
NOTE: The blower motor, recirculation control motor
and blower resistor can bs replacsd without rsmoving
th€ blower unit (see neld Page).
1. Move the temperature control to "HOT."
'96-98: Slide the temperature control lever.'99-00: Turn the ignition switch ON (ll), then turn
the temperature contol knob. Turn the ignition
switch off,
Remove the glovs box (ses ssction 20),
R€move ths s6lf-tapping screw and ths passsng6r's
dashboard low€r cover. Removo the bolt, the nut
and the kn€e bolst€r, then remove the fiv€ bolts and
the glove box trame,
Without Air Condhioning
4-a. Remove the wiro harness from the h68t€r duct, then
remove the two self-tapping scrsws and the heatsr
duct.
KNEE
GLOVE BOX FRAME
HEATER DUCT
21-37
Wrth Air Conditioning
4-b. Removo th6 ev8porator (sss pago 22-28).
6x1.0m|n9.8 N'm
6x1.0mm9.8 N'm lt'o tgf'm, t.2 lb{'ttl
Disconnoct the connectors trom th€ blower motor,
blowor r6sistor {'96 - 98 models), power transiator
('99 - 0O modsls), blowor motor high telay ('99 - 00
models) and recirculation control motor.
R€mov€ ths wiro harnoss clip from tho recirculation
control motor, and release the wir6 harnsss from ths
clamo on the blowor unit. Remove the two mount-
ing bolts, tho mounting nut and ths blowor unit'
9.8 .m 11.0 tgfm,1.2 tblfrl
lnstall in ths reverso order of removal. Mako surs
that thsre is no air leaka96.
6x1.0mm9,t N'm 11.0lgi.m,7.2 tbf.fil

Overhaul -'96 - 98 Models
HEATER FAN SWITCHTest, page 21-49
Air Mix Control Cable Replacomenl
1. Cut the inner cable on the lever side of the cable holder, then remove both pieces of the inner cable.
2. Using a sharp knife, cut completely through the end of the cable housing at the two locations.
3. Slidethe largesection ofthecable housing outofthe cable holder, being careful not to da mage the cable stops.
4. Carefully remove the cut pieces of the cable housing with a small flat tip screwdriver.
5. Hook the tip of the new air mix control cable to the temperature control lever, then push the cable housing into the
cable holder until it locks into place.
NOTE: After assembly, check that the temperature control lever slides smoothly through the full stroke lrom right to left.
21-43

Temperature Control
Adjustment -'96 - 98 Models
1. From under the hood, disconnect the heater valve
cable from the heater valve.
TERVALVECABLEHEATER VALVE ARM
2.From under the dash, disconnect the air mix control
cable housing from the cable clamp,
AIR MIXCONTROLARM
3.Set the temperature control lever to MAX. COOL.
With the air mix control cable attached to the air
mix control arm, gently pull on the outer cable
housing to fully close the door and to remove any
slack in the cable. Don't pullto hard, or the temper-
ature control lever will move.
Hold the air mix control arm against the stop. then
snap the air mix control cable housing into the
cable clamp.
21-44
6. From under the hood. move the heater valve arm to
the fully closed position. then attach the heater
valve cable to the heater valve arm.
7. Hold the heater valve arm in the closed position,
and gently pull on the heater cable outer housing to
take up any slack. then install the heater valve cable
housing into the cable clamp.
HEATER VALVE ARM

Adjustment -'99 - 00 Models
1. From under the hood, open the cable clamp, then
disconnect the heater valve cable from the heater
valve arm.
From under the dash. disconnect the heater valve
cable housing from the cable clamp, and disconnect
the heater valve cable from the air mix control arm.
HEATER VALVE CABLE
Set the temperature control dial on MAX COOL with
the ignition switch ON {ll).
Attach the heater valve cable to the air mix control
arm as shown above. Hold the end of the heater
valve cable housing against the stop, then snap the
heater valve cable housing into the cable clamp.
HEATER VALVE ARM
5. From under the hood. turn the heater valve arm to
the fullv closed oosition as shown, and hold it,
Attach the heater valve cable to the heater valve
arm, and gently pull on the heater valve cable hous-
ing to take up any slack, then install the heater valve
cable housing into the cable clamp.
HEATER VALVE ARM
21-45

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

A/C Service Tips and Precautions
The air conditioner system uses HFC-134a (R-134a) refrigerant and polyalkyleneglycol (PAG) refrigerant oil*, which are not
compatible with CFC-12 (R-12) refrigerant and mineral oil. Do not use R-12 refrigerant or mineral oil in this system, and do
not attempt to use R-12 servicing equipmenU damage to the air conditioner system or your servicing equipment will result.*Sanden SP-10:
. P/N 38897 - P13 - A0lAH: 120 ml 14ll.oz, 4.2lmp.oz)
. P/N 38899 - P13 - A0l | 40 mf 11 1/3ll.oz,1.4 lmp'oz)
Use only service equipment that is U.L. listed and is certified to meet the requirements of SAE J2210 to remove R 134a
from the air conditioner system.
CAUTION: Exposure to air conditioner ref;ige;ant and lubricant vapol or mist can irritate syes, nose and throat, Avoid
breathing the air conditioner refrigerant and lubricant vapor or misl.
lf accidental system discharge occurs, ventilate work area before resuming service.
R-'134a service equipment or vehicle air conditioner systems should not be pressure tested or leak tested with compressed
ai.
!@@ some mixtures of air and R-t3ila have been shown to be combustible at elevated pressures and can result
in tire or explosion causing iniury or property damage. Never use compressed air lo pressure tesl R-134a service equip-
ment or vehicle 8ir conditioner systoms.
Additional health and safety information may be obtained from the refrigerant and Iubricant manufacturers.
L Always disconnect the negative cable from the battery whenever replacing air conditioning pans.
2. Keep moisture and dust out of the system. When disconnecting any lines, plug or cap the fittings immediately; don't
remove the caps or plugs until just before you reconnect each line.
3. Before connecting any hose or line, apply a few drops of refrigerant oilto the O-ring.
4, When tightening o. loosening a fitting, use a second wrench to support the matching fitting.
5. When discharging the system, use a R-134a refrigerant recovery/recycling/charging station; don't release refrigerant
into the atmosphere,
6. Add refrigerant oil after replacing the following parts:
NOTE:
. To avoid contamination, do not return the oil to the container once dispensed, and never mix it with other refriger-
ant oils.
. lmmediately after using the oil, replace the cap on the container, and seal it to avoid moisture absorption.
. Do not spill the refrigerant oil on the vehicle; it may damage the paint; if the refrigerant oil contacts the paint, wash
it off immediately.
Condenser .......2o ml (2/3 fl.oz, 0.7 lmp.ozl
Evaporator .,.,.,. i[5 m{ 11 213 tl.oz,1,6lmp.ozl
Line or hose ..... 10 mf (1/3 fl.oz, 0.4 lmp.ozl
Receiver/Dryer 10 m{ (1/3 fl.oz,0.'l lmp.ozl
Leakage repair 25 m{ (5/6 fl.oz, 0.9 lmp.ozl
Comptessor ... For compressor replacement. subtract the volume of oil drained trom the
removed compressor from A, and drain the calculated volume of oilfrom the new
compressor: A - Volume of removed compressor: Volume to drain from new
comoressor.
A: SANDEN 130 mf l/t 113 ll.oz, 4.6 lmp'ozl; DENSO 140 mf {4 213 ll'oz, 1.9
lmp.oz),
NOTE: Even if no oil is drained from the removed compressor, don't drain more
than S0 m{ 112Ell.oz,1.8 lmp.oz) fromthe new compressor.
REMOVED NEW
COMPRESSORCOMPRESSOR
*DENSO ND-OlL 8l
. P/N 38897 - PR7 - A01AH: 120 ml (4 fl.oz)
. P/N 38899 PR7-A01:40mf (1 1/3fl'oz)
rereW W0000
22-22
-0_!- -0_a
Tol l00l
| | lffi 1 onrrrutrc I
fi+-sAME
LEvEr...+jEf,voLUME
J
^

A/C System Service
Performance Test
The performance test will help determine if the air con-
ditioner system is operating within specifications.
Use only service equipment that is U.L.-listed and is cer-
tified to meet the reouirements of SAE J2210 to remove
HFC-134a (R-134a) from the air conditioner system.
CAUTION: Exposure to air conditionor rofrigerant and
lubricant vapor or mist can irrilalo €yes, nose and
throat. Avoid breathing tho air conditioner rstrigerrnt
and lubricant vapor or mist,
lf accidental system discharge occurs, ventilate work
area before resuming service.
R-134a service equipment or vehicle air conditioner sys-
tems should not be pressure tested or leak tested with
compressed air.
@ some mixtur$ of air and R-134a have been
shown lo b9 combustible rt glgvatad pr€ssur63 and can
resull in tire 01 oxplosion causing inlury ot property
damage. Never uao compre33ed air to pressure t99t R-
134a ssrvico 6quipmsnt or vohicla air conditioner sys-
tems.
Additional health and safety information may be obtained
from the refrigerant and lubricant manufacturers.
'1. Connect a R-134a refrigerant recover/recycling/
charging station to the vehicle, as shown, following
the equipment manufacturer's instructions.
2. lnsert a thermometer in the center vent outlet.
Determine the relative humidity and air tempera-
ture,
Test conditions:
. Avoid direct sunlight.
. Open hood.
. Open front doors.
. Set the temDerature control lever or dial to MAX,
COOL, the mode control switch or dial on VENT
and the recirculation control switch on RECIRCU-
LATE.
. Turn the A,/C switch on. and the heater fan switch
on MAX.
. Run the engine at 1,500 rpm.
. No driver or passengers in vehicle
After running the air conditioning for 10 minutes
under the above test conditions, read the delivery
temperature from the thermometer in the dash vent
and the high and low system pressure from the A,/C
gauges.
Recovery/Rocycling/Charging Station
22-24