ACURA NSX 1997 Service Repair Manual

THROTTLE VALV E CONTRO L
MOTO R RELA Y
ECM
FAN CONTRO LUNIT
RADIATO R FA N CONTRO L SENSO R
Test , pag e 23-12 0 ENGIN
E COMPARTMEN T FA N MOTO R (A/T )
Test , pag e 23-11 8
Replacement , pag e 23-11 8
ENGIN
E COMPARTMEN T
FAN RELA Y (A/T )Wire colors : YEL/BLK ,
BLU/RED , WHT/GRN ,
and WHT/BL U
Test , pag e 23-11 9
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Radiator and Condenser Fan Controls

Description

Fan control system:

The cooling fan system is comprised of the radiator fan, condenser fan (left and right), engine compartment fan, radiator

fan low relay, radiator fan high relay, condenser fan relay, engine compartment fan relay, radiator fan resistor, radiator

fan control sensor, A/C pressure switch, fan control unit, climate control unit, and ECM.

The fan control unit controls the operation of the radiator fan and condenser fans.

It uses inputs from the radiator fan control sensor and the A/C pressure switches (A and B) in the A/C system to deter-

mine when the fans should run and at what speed.

Additionally, the temperature switch shuts down the A/C system if the engine coolant temperature (ECT) exceeds

266°F (130°C). If the pressure in the A/C system is higher than normal, pressure switch A closes and the fans will run at

high speed only. See the A/C section for the description and specifications of that function.ProCarManuals.com

NOTE: Th e number s i n th e tabl e sho w th e troubleshootin g sequence .
Troubleshootin g
*: Refe r t o sectio n 2 2 fo r A/ C pressur e inspectio n o f th e A/ C system .
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Radiator and Condenser Fan Controls

Control Unit Terminals

THROTTLE VALVE CONTROL

MOTOR RELAY

Wire

Terminal Color
Connects to

1

2

3

4

5

6

7

8

9

10

11

12
-

LT GRN

GRY/BLK

BLU/RED

BLK

BRN/BLK

GRN

—

ORN/BLU

BLU/BLK

YEL/BLK

GRN/BLK
Not used

Radiator fan control sensor

Climate control unit

Radiator fan high and engine

compartment fan relays coil

Ground (G401, G402, G403)

A/C triple pressure switch A

Radiator fan control sensor

Not used

Condenser fan relay coil

ECM
(ACS)

IG2 (Power supply)

Radiator fan low relay coil
1. Disconnect the 3P connector from the resistor.

3P CONNECTOR
RADIATOR

FAN

RESISTOR

NOT USED

2. Using an ohmmeter, measure resistance between

the A and B terminals. Replace the resistor if the

resistance is not within specifications.

NOTE: Resistance will vary with the resistor

temperature; specifications are at 68°F (20°C).

Radiator Fan Resistor

Resistance: 0.54—0.66 ohms
Radiator Fan Resistor TestProCarManuals.com

Radiator Fan Motor Test

1. Disconnect the 2P connector from the radiator fan

motor.

2. Test the motor by connecting battery power to the

A terminal, and ground to the B terminal.

3. If the motor fails to run or does not run smoothly,

replace it.
Condenser Fan Motor Test

1. Disconnect the 2P connector from the condenser

fan motor.

NOTE: The illustration shows the right condenser.

2. Test the motor by connecting battery power to the

A terminal, and ground to the B terminal.

3. If the motor fails to run or does not run smoothly,

replace it.ProCarManuals.com

Radiator and Condenser Fan Controls

Engine Compartment Fan Motor

Test (A/T)

1. Disconnect the 2P connector from the engine

compartment fan motor.

2. Test the motor by connecting battery power to the

A terminal, and ground to the B terminal.

3. If the motor fails to run or does not run smoothly,

replace it.
Engine Compartment Fan Motor

Removal (A/T)

1. Disconnect the 2P connector from the engine

compartment fan motor.

2. Remove the engine compartment fan relay, the test

tachometer connector, and the engine wire harness

from the engine compartment fan shroud.

3. Remove the three mounting bolts.

MOUNTING BOLT

6 x 10 mm

12 N-m (1.2 kgf-m, 9 Ibf-ft)
TEST TACHOMETER

CONNECTOR

WASHER

(Corrosion

resistant)

ENGINE COMPARTMENT

FAN RELAYProCarManuals.com

Fan Relay Tests

Check continuity at the relay terminals.

There should be continuity between the C and D ter-

minals.

There should be continuity between the A and B ter-

minals when power and ground are connected to the

C and D terminals.

There should be no continuity between the A and B

terminals when power is disconnected.

Radiator fan low relay
Engine compartment fan relay (A/T)

Radiator fan high relay

Condenser fan relayProCarManuals.com

Radiator an d Condense r Fa n Control s
Radiator Fa n Contro l Senso r Tes t
NOTE : Blee d ai r fro m th e coolin g syste m afte r install -
in g th e radiato r fa n contro l senso r (se e sectio n 10 ).
1 . Remov e th e radiato r fa n contro l senso r fro m th e
thermosta t cover .
2 . Suspen d th e radiato r fa n contro l senso r i n a con -
taine r o f coolan t a s shown .
THERMOMETE R
RADIATOR FA N
CONTRO L SENSO R
ENGIN E
3. Hea t th e coolant , an d chec k coolan t temperatur e
wit h a thermomete r (se e tabl e below) .
4 . Measur e th e resistanc e betwee n th e A an d B ter -
minal s accordin g t o th e table .
5 . I f unabl e t o obtai n th e abov e readings , replac e th e
radiato r fa n contro l sensor .
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Gauge Assembl y
Gauge/Terminal Location Index
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 .
SPEEDOMETER :Indicates 6 0 mp h [60km/h ] a t 1.02 6 [637 ]
rp m o f th e vehicl e spee d senso r (VSS) .
FUE L GAUGE :
• Gaug e test , pag e 23-13 4
• Sendin g Uni t Test , pag e 23-13 5
VOLTAG E METER :
If, wit h th e No . 5 (1 5 A ) fus eand othe r gauge s
OK , th e pointe r o f th e
voltag e mete r doe s
no t mov e a t all ,
replac e th e voltag e
meter .
TACHOMETER :Indicates 10 0 rp m a t 30 0 pulse s pe r minut eof th e ignite r unit .
COOLAN T TEMPERATUR E GAUGE :• Gaug e Test , pag e 23-13 6
• Sende r Test , pag e 23-13 6
SAFET Y INDICATO R SYSTEM :
Se e pag e 23-156 ENGIN
E OI L PRESSUR E
GAUGE:Test pag e 23-13 7
A/ T GEA R POSITIO N
INDICATO R SYSTE M
Se e pag e 23-158
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Gauge Assembl y
Removal
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 .
1 . Remov e th e dashboar d lowe r cover , an d disconnec t
th e floo r wir e harnes s connectors .
2 . Remov e th e tw o screws , the n remov e th e dashboar d
lowe r pa d fro m th e dashboard .
DASHBOAR DLOWERCOVER
DASHBOAR DLOWER PA D 3
. Remov e th e thre e screws , the n remov e th e til t cove r
fro m th e steerin g column .
TILT COVE R
4. Disconnec t th e connector s fro m th e instrumen t
panel switches .
5 . Remov e th e si x screws , the n remov e th e instrumen t
pane l tri m fro m th e dashboard .
INSTRUMEN T PANE L TRI M
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