1996 HONDA CIVIC thermo

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

Circuit Diagram
UNDER DASHFUSE/RELAY 8OX
N0.17 (7.54)
'96 - 98 Models
UNDER.HOOD FUSEi BELAY BOX
WHT/SLU BLKYEL
BLK
+
G751
3
'o
I8LK
I
G40lG402
GNITON SWITCH
N0.41 (8rA) N0.42 (40A)
COMPBESSORCLUTCHBELAY
BLUMHT
,l
(E) i,T'
BLUi BED
A/c ITHERMOSTAI BLU/REO
CONDENSEFFAN MOTOR
*F,.X,
FAN rl
BLK
{
G401G402
HEATERswrlcH
32
22-6

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

Ftom page 22 18
Check tor an open in the wire:1. Turn the ignition switch OFF,then disconnect the iu mper
2. Remove the center dashboardlower cover lsee section 20),
and disconnect the heater con'
trol panel 14P connector.
3. Turn the ignition switch ON (ll).
4. Measure the voltage betweenthe No. 11 terminal and bodyground.
Repair op6n in the wire bstween
the A/C th€rmostat and th6 hoater
control panel.
Check lor an open in the wire:
1. Turn the ignition switch OFF.2. Disconnect the heater Ian
switch 6P connector,3. Check for continuity between
the No. 14 terminal of theheater control panel 14P con_nector and the No.6 terminalof the heater fan switch 6P con-nector.
Repair open in the wiro betweGnthe heal.r control Panel and theheater fan switch.
Check for an open in thG wire:Check for continuity between theNo. 1 terminal of the heater lanswatch 6P connector and bodYground.
Chock tor an open in tho wir€
between the heater lan switch
and body ground. lf the wire is OK,check for poor ground at G401 sndG402.
ls there continu;ty?
ReDlace the heater tan switch.ls the heater fan switch OK?
Check for loose wiaes or poor
connections at the heater controloanel 14P connoctor and hoetertan 3witch 5P conn€clor and atthe A/C thermostet 3P connec-tor. ll the connections are good,
raplace the heator control Panel.
r'oA - qe m^.lalal
HEATER CONTROL PANEL lilP CONNECTOR
tra6
7II'o lx't1121314
BLU/RED
Wire side of female terminals
HEATER CONTROL PANEL 1'P CONNECTOR
Wire side of female terrninals
HEATER FAN SW]TCH 6P CONNECTOR
Wire side of female terminals
(cont'd)
12;--?45
7I10X'll121314
GRN
123
a56GRN
22-19

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
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