1997 HONDA CIVIC air conditioning contro

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 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

l'f .
Electrical
Special Toofs .,....................,23-2
Troubleshooting
Tips and Precautions ..............,.................... . 23-3
Five-step Troubleshooting .............. ......... . . 23-5
wire color codes ..........,23-5
Schematic Symbols ........,................... . . .. .... 23-6
Relay and Control Unit Locations
Engine Compartment ...,..................... ... .. . 23'7
Dashboard ......................23-8
Dashboard/Door ......... 23-12*Airbags ................. ....... Section 24
Air Conditioning ......... Section 21
Aftelnator ..........."""" """ 23-112
Anti-lock Brake System {ABS) Section 19*A/T Gear Position Indicator .....................,. .... ... 23-149
Automatic Transmission Svstem .... . ....... Section 14
Batterv ......... . . . ... ...... .......23-91
Blower controls .. . ... Section 2l
Charging System ....'...........23'112
Connector ldentilication and Wire Harness
Routing .................. ......23'13
Cruise Control ............,........23-240
Dash Lights Brightness Controller ............. ....... 23-180
Fan controfs "" 23'126
Fuel PumD ........ . ........ section 11
Fuses/Refay ...............,..,,.. 23'62
PGM-FI Control System ......................,....... Section 1 1
*Gauges
Circuit Diagram ....,.,.......23-131
Fuef Gauge ...........'.'.......23-142
Gauge/lndicator .. . .. 23-129
Ground Distribution .. . 23-75
Heatei controls .. . ..... Section 21*Horn................. ...............23-196
*tgnition Switch ....................23-89
lgnition System .......,.... 23-102
*lntegrated Control Unit ....................................... 23-156
fnterlock System ,........ . . , ,23-144
Lighting System . . . .. ......... 23-161
Lights, Exterior
Back-up Lights ..'............23'171
Brake Lights .................. 23'174
Daytime Bunning Lights (Canadal ............... 23'166
Front Parking Lights ......,................ .'. .......... 23-167
Front Turn Signal Lights .......... . . ............ ..,.23-167
Headtights ....".'....-... ..... 23'167
High Mount Brake Light ...................... ... .23'179
License Plate Lights ...... 23'176
Taitfights ................ .......23'171
lnterior Lights ..-.......,, . 23-142
Moonroof ..,.................,........ 23-235
Power Distribution ....... . . .23-61
Power Door Locks .......,,,. .23'251
Power Mirrors ,..............,.,...23'206
Power Relays ....... . ...... . . .. 23-86
Power Windows ............,,....23-220
Rear Window Defogger .......................... . . ... . . 23-2OO
Spark Plugs . ..... . ........ .....23-111
Slarting System ................23-93*stereo Sound Svstem ,................. ..... ... . ... ,.,.,,23'147'Supplemental Restraint System (SRS) ... . Section 24
Turn Signal/Hazard Flasher System .......'.'....-... 23-173
*Undel-dash Fuse/Relay Box ............,.................. 23-85
vehicfe soeed sensor (VSSI """" ""' 23-140+Wipers/Washers .........,.,.,...23-214
NOTE: Unless otherwise specified, references to auto-
matic transmission (Mf) in this section include the CVT.

- How the Circuit Works
Battery voltage is supplied through tuse 56 to the
A,/C compressor clutch r€lay contacts at all times.
With the ignition switch in ON (ll), vollage is applied
to the coil of the A,/C compressor clutch relay
through fuse 17. When you push the A,/C switch
ON, and the heater fan switch is in position | , 2, 3,
or 4, a "ground" input is provided to the engine
control module (ECM) or powertrain control module
(PCM) through the l'lC thermostat and the l'lC
pressure switch.
The A,/C compressor clutch relay is grounded by the
engine control module (ECM) or powertrain control
module (PCM). When energized, the A'lC
compressor clutch relay allows battery voltage to
turn on the A,/C comDressor clutch.
The A,/C ON indicator light comes on when the A,/C
system is requested.
A,/C Thermostat
The A'lC thermostat is located on the evaoorator
housing. The A,/C thermostat turns off the A,/C
compressor clutch if the temperature at the
evaporator goes below 3'C (37'F). This prevents
condensation from freezing on the evaporator fins
and blocking the air delivery into the passenger
compartment. The blower motor will keep running
when the sensor turns off the comDressor.
A,/C Pressure Switch
The fuC oressure switch is located in the condenser
outlet line where refrigerant is in a high
temperature/high pressure liquid state. The switch
will sense abnormally high or low pressure, and
open the circuit. This removes ground, and the
compressor will stop running.
Thermal Protectot
The thermal protector, located on the A,/C
compressor, opens and turns the compressor off if it
senses high temperature. Once the compressor
cools, the switch will close and the compressor will
begin running again.
Refer to the Service Manual (Section 22,
Air Conditioning) for specific tests or
troubleshooting procedures.
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