1997 ACURA NSX Service Repair Manual

Engine Cover/Roo f Cove r
Replacemen t (cont'd )
3. Remov e th e roo f sto p bracket s an d hoo k stop s fro m
th e engin e cover .
LEFT ROO F STO P BRACKET /
ROO F HOLDE R SWITC H RIGH
T
ROO F STO PBRACKE T
ENGINECOVER
HOOK STOP S
CONNECTO R
LEF T ROO F
STO P BRACKE T
This scre w o n th e righ troof sto p bracke t i sscre w A . Nu
t locations , 4
HOOK STO P
4. Installatio n is th e revers e o f th e remova l procedure .
NOTE:
• Mak e sur e th e roo f cove r open s properl y an d
lock s securely .
• Mak e sur e th e roo f fit s o n th e engin e cove r
securely .
HOOK
STO P
ROO
F HOLDE R
SWITCH
ROOF SID E
HOO K
ENGIN ECOVER ROO
F
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22-88
22-49
Specia l Tool s
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MODE CONTRO L MOTO R
Replacement , pag e 22-5 7
Test , pag e 22-5 8
EVAPORATO RTEMPERATUR ESENSORRemoval , pag e 22-6 5
Test , pag e 22-6 5 SUNLIGH
T SENSO R
Removal , pag e 22-6 3
Test , pag e 22-6 3
CLIMAT E CONTRO L UNI T
Replacement , pag e 22-5 4
Adjustment , pag e 22-5 5COMPRESSO R (NIPPONDENSO )
Compresse s th e refrigeran t an d
the n force s i t throug h th e condenser .
"DEF " DOO R
Adjustment , pag e 22-7 7"HEAT " DOO RAdjustment , pag e 22-7 7
BLOWE R UNI T
Replacement , pag e 22-6 7
Overhaul , pag e 22-6 8
RECEIVER/DRYE RServes a s a reservoi r whic h filter s an dremove s moistur e fro m th e refrigerant .
IN-CAR TEMPERATUR E SENSO R
Removal , pag e 22-6 1
Test , pag e 22-6 1
HEATER-EVAPORATO R
UNITReplacement , pag e 22-7 4
Overhaul , pag e 22-7 6
OUTSID E AI R TEMPERATUR E SENSO R
Removal , pag e 22-6 2
Test, pag e 22-6 2DUAL CONDENSE RDissipates th e hea t whic h wa sabsorbe d b y th e refrigerant .
Replacement , pag e 22-7 9
Overhaul , pag e 22-8 0
HEATE R COR E
TEMPERATUR E SENSO R
Removal , pag e 22-6 4
Test, pag e 22-6 4
AIR MI X CONTRO L
MOTO R
Replacement , pag e 22-5 6
Test , pag e 22-5 7
RECIRCULATIO
N
CONTRO L MOTO R
Replacement , pag e 22-5 9
Test , pag e 22-5 9 HEATE
R VALV E CABL E
Adjustment , pag e 22-58 , 22-7 5
VENT DOO R CONTRO L
MOTO R
Replacement , pag e 22-6 0Test, pag e 22-6 0
A/C TRIPL EPRESSUR E SWITC H
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Heater-Evaporator Door Position

(MAX COOL)

U.S.A model

VENT DOOR

DEFROSTER

DOOR

HEAT

DOOR

AIR MIX DOOR

HEATER CORE
A/C EVAPORATOR

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Description
Outline
The ai r conditionin g remove s th e hea t fro m th e passenge r compartmen t vi a th e rout e show n below .
Using th e refrigeran t (R-134a )
Section/compressio n
High temperature /high pressur e ga s
COMPRESSO R
Less moisturize dlow pressur e vapo r
Radiatio n o f hea t
High temperature / Hig h temperature /high pressur e liqui d Trap s debris and act s hig h pressur e liqui das a n accumulator .
RIGHT/LEFTCONDENSE RRECEIVER/DRYE R
Absorption o f hea t
EVAPORATO R
More liquefie dlow pressur e vapo r
EXPANSIO N VALV E
RECEIVER/DRYE R
COMPRESSOR
LEFTCONDENSE REXPANSIONVALVEHEATE RCORE
This vehicl e use s HFC-134 a (R-134a ) refrigeran t whic h doe s no t contai n chlorofluorocarbons . Pa y attentio n t o th e follow -
in g servic e items :
• D o no t mi x refrigerant s CFC-1 2 (R-12 ) an d HFC-134 a (R-134a) . The y ar e no t compatible .
• Us e onl y th e recommende d polyalkyleneglyco l (PAG ) refrigeran t oi l (ND-OI L 8 ) designe d fo r th e R-134 a compressor .
Intermixin g th e recommende d (PAG ) refrigeran t oi l wit h an y othe r refrigeran t oi l wil l resul t i n compresso r failure .
• Al l A/ C syste m part s (compressor , discharg e line , suctio n line , evaporator , condenser , receiver/dryer , expansio n valve ,
O-ring s fo r joints ) hav e t o b e prope r t o refrigeran t R-134a . D o no t confus e wit h R-1 2 parts .
• Us e a haloge n ga s lea k detecto r designe d fo r refrigeran t R-134a .
• R-1 2 an d R-134 a refrigeran t servicin g equipmen t ar e no t interchangeable . Onl y us e a Recovery/Recycling/Chargin g
Syste m tha t i s U.L.-liste d an d i s certifie d t o mee t th e requirement s o f SA E J221 0 t o servic e R-134 a ai r conditionin g
systems.
• Alway s recove r th e refrigeran t R-134 a wit h a n approve d Recover/Recycling/Chargin g System , befor e disconnectin g
any A/ C fitting .
RIGHTCONDENSE R EVAPORATO R
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A/C Triple Pressure Switch

Construction

The A/C triple pressure switch consists of a High-Low pressure switch (A/C pressure switch A) and a Middle pressure

switch (A/C pressure switch B).

High-Low pressure switch

If the refrigerant pressure becomes too high (due to blockage), or too low (due to leakage), the A/C triple pressure

switch sends a signal to the fan control unit to prevent the compressor from operating.

Operate the compressor

Stop the compressor

Middle pressure switch

If the refrigerant pressure goes above or below 1,550 kPa (15.5 kgf/cm2, 220 psi), the A/C triple pressure switch sends a

signal to the ECM, then the ECM operates the idle control.

A/C

TRIPLE

PRESSURE

SWITCH
HIGH-LOW

PRESSURE

SWITCH

MIDDLE

PRESSURE

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Description

Fan Control Unit

The fan control unit performs calculations based on signals from the radiator fan control sensor. It them controls the

operation of radiator fan speed (High-Low), engine compartment fan, condenser fan and A/C compressor.

When engine coolant temperature is above 183°F

(84°C), the fan control unit turns Tr1 ON and

radiator fan runs at low speed.

When engine coolant temperature is above 194°F

(90°C), the fan control unit turns Tr2 ON, and

radiator fan runs at high speed and engine

compartment fan comes on.

When engine coolant temperature is above 266°F

(130°C), the fan control unit turns Tr3 OFF, and

stops the condenser fan. Then it turns Tr4 OFF,

and stops the compressor.

IG2

RADIATOR FAN (Low)

RADIATOR

FAN CONTROL

SENSOR
RADIATOR FAN (High)

ENGINE COMPARTMENT

FAN

CONDENSER FAN

(Right and Left)

ECM
(ACS)

A/C

TRIPLE

PRESSURE

SWITCH

GND
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