ACURA NSX 1997 Service Repair Manual

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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

SWITCHProCarManuals.com

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
A/C SWITCHProCarManuals.com

SRS component s ar e locate d in thi s area . Revie w th e SR S componen t locations , precautions , an d procedure s in th e SR S
sectio n 24 befor e performin g repair s o r service .
UNDER-HOO D RELA Y BO X BBLOWE R MOTO R RELA Y
BLOWE R MOTO R HIG H RELA Y
COMPRESSO R CLUTC H RELA Y
POWER TRANSISTO R
BLOWE R MOTO R
RECIRCULATIO N
CONTRO L
MOTO R
CONDENSE R
FA N MOTO R UNDER-HOO
D RELA Y BO X A
(CONDENSE R FA N RELAY )
HEATER COR E TEMPERATUR E SENSO R
CLIMAT E CONTRO L UNI T VEN
T DOO R
CONTRO L MOTO R
OUTSID E AI RTEMPERATUR E SENSO R
A/C TRIPL E PRESSUR E SWITC H
ENGIN E COMPARTMEN T
FUSE/RELA Y BO X
FAN CONTRO L UNI T(Fan radiato r an d con -
dense r fan s insid e th e
vehicle , behin d seats )
EVAPORATO RTEMPERATUR E
SENSO R
MOD E CONTRO L
MOTO R
IN-CA R
TEMPERATUR E
SENSO R AI
R MI X CONTRO L MOTO R
UNDER-HOO
D
FUSE/RELAYBOX
SUNLIGH TSENSOR
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Troubleshooting
Self-diagnosis Circui t Chec k
The Automati c Climat e Contro l Syste m ha s a built-i n sel f diagnosi s feature . T o ru n it , tur n th e ignitio n switc h O N (II) ,
the n tur n th e fa n spee d dia l t o th e AUT O position . Se t th e temperatur e contro l dia l t o 60° F (18°C) , the n graduall y mov e
the dia l u p th e temperatur e rang e to 90° F (32°C) . A t eac h temperatur e setting , pus h bot h th e AUT O an d OF F button s
on th e contro l uni t a t th e sam e time . Wai t fo r a t leas t on e minut e fo r th e syste m to readjus t an d chec k fo r problems .
I f an y problem s ar e foun d i n circuit s "A " throug h "I" , th e syste m wil l indicat e whic h circui t ha s th e proble m b y lightin g
th e respectiv e indicato r light .
NOTE : Th e climat e contro l uni t doe s no t memoriz e whic h self-diagnosi s indicato r light s com e on . I f yo u tur n th e ig -
nitio n switc h OFF , th e indicato r ligh t memor y wil l b e lost .
AUT O BUTTO NOFF BUTTO N
TEMPERATUR E TEM P DISPLA Y
CONTRO L DIA LFAN SPEE D DIA L
NOTE :
• Whe n yo u tur n th e ignitio nswitch OFF , th e self-diagnosi s functio n wil l b e canceled .
• After completin g repair work, run th e self-diagnosi s agai n to mak e sure that ther e are n o othe r malfunctions .
22-16
22-18
22-2 0
22-2 2
22-2 4
22-2 6
22-2 8
22-3 0
22-3 2
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Function Selection and Operation Check

This check will quickly and automatically select and operate all functions of the climate control system, in the combina-

tions and sequence shown below. It may help clarify a problem, or identify one that didn't show up when you perform

the self-diagnosis circuit check.

Turn the FAN switch to AUTO, then push in both the MODE and AUTO buttons and hold them in while you start the

engine. The control unit will then automatically run the check in eight steps, one step every five seconds.

To stop at one of those steps, push the MODE button; to continue, push it again for each step after that.

Pushing the OFF button or turning the ignition OFF, will turn off the check.

Check the temperature, volume, and source of the air flow, and compare it to what the chart shows it should be.ProCarManuals.com

Use thi s char t i f th e self-diagnosi s check s don' t identif y an y caus e fo r th e symptom .
Acros s eac h ro w in th e chart , th e potentia l source s o f a sympto m ar e ranke d in th e orde r the y shoul d b e inspected , start -
ing wit h Fin d th e sympto m in th e lef t column , rea d acros s t o th e mos t likel y source , the n refe r t o th e pag e liste d a t th e
top o f tha t column . I f inspectio n show s th e componen t i s OK , tr y componen t etc .
Symptom-to-Component s Char t
Troubleshootin g
22-34 22-16 22-18 22-20 22-22 22-24 22-26 22-28 22-30 22-32 22-36 22-40 22-42 22-44 22-48
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Climate Control Unit Input/Output Signals

CLIMATE

CONTROL UNIT

View from wire sideProCarManuals.com

Climate Contro l Uni t
Replacemen t
SRS component s ar e locate d in thi s area . Revie w th e SR S
componen t locations , precautions , an d procedure s i n th e
SR S sectio n 24 befor e performin g repair s o r service .
1. Remov e th e cloc k (se e sectio n 23 ).
2 . Remov e th e tw o screw s behin d th e clock , the n
remov e th e cente r ai r ven t (se e sectio n 20 ).
3 . Tak e ou t th e ashtra y an d remov e th e tw o screw s
fro m unde r th e ashtray .
ASHTRA Y
4. Remov e th e fou r screws , the n remov e th e cente r
armrest .
PAD
CENTE R ARMRES T
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