ACURA NSX 1991 Service Repair Manual

Adjustment
The calibratio n switc h can rais e o r lowe r th e se t temper -
ature b y ± 3° F (1.5°C ) i n relatio n t o th e digitally -
displayed temperature .
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Air Mix Control Motor


Replacement

1. Disconnect the heater valve cable from the air mix control motor.

HEATER VALVE
CABLE

AIR MIX CONTROL

MOTOR

2. Remove the three screws and the air mix control
motor.

AIR MIX CONTROL

MOTOR

3. Install the air mix centrol motor in the reverse order of removal, then apply battery voltage (see page

22-57) and watch the door move.

Make sure that the air mix door moves smoothly

without binding.

Make sure the motor doesn't pull the air mix

door too far.
4. If necessary, to adjust the heater valve cable:
Set the air mix control motor at COOL position

(see page 22-57) with the cable disconnected

at the valve.
Hold the end of the cable housing against the
stop on the cable. Then snap the clamp down

ove
r
the housing.

After adjusting the cable, make sure that the air
mix control motor still moves smoothly without

binding.

STOP

CLAMP

HEATER VALVE

CABLE
AIR MIX CONTROLMOTOR
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Test

1. Connect battery power to the No. 1 terminal of the air mix control motor, then connect ground to the
No. 2 terminal; the air mix control motor should
run, and stop at HOT,
If it doesn't, reverse the connections; the air mix
control motor should run, and stop at COOL.
NOTE: If the air mix control motor does not run,
remove it, and check the air mix control linkage and
doors for smooth movement. If the air mix control
linkage and doors move smoothly, replace the air

mix control motor.

2. Measure resistance between the No. 3 terminal and No. 5 terminal; it should be approx. 10 k. 3. • Measure resistance between the No. 3 terminal and
No. 4 terminal; if should be approx. 0.6 k
at COOL

and approx. 9.4 k at HOT.
Mode Control Motor

Replacement

1. Remove the three screws and mode control motor.

MODE CONTROL

MOTOR

2. Install the mode control motor in the reverse order of removal. Then apply battery voltage (see page
22-58) and watch the doors
move.

Make sura that the HEAT and DEF doors moves

smoothly without binding.

Make sure the motor doesn't pull the HEAT and
DEF doors too far.ProCarManuals.com

Mode Control Motor

Test

1. Disconnect the mode control motor connector, turn

the ignition switch ON (II), and move the blower

switch to the middle setting.

2. Connect battery power to the No. 1 terminal of the

mode control motor, then connect ground to the No.

2 terminal. The mode control motor should run, and

stop at VENT.

If it doesn't, reverse the connections; the mode

control motor should run, and stop at DEF.

NOTE: If the mode control motor does not run,

remove it, and check the mode control linkage and

doors for smooth movement. If the mode control

linkage and doors move smoothly, replace the

mode control motor.
3. Plug the connector back into the motor. Operate

the mode switch on the climate control unit to each

mode. Verify that the mode control motor has mov-

ed to the selected position by checking the air flow

for the mode selected.

NOTE: If the motor did not move, turn the ignition

switch OFF, and disconnect the mode control mo-

tor connector. Turn the ignition switch ON (II), then

connect battery power to No. 1 and No. 2 terminals

as shown in step 2. Power the mode control motor

to move the doors to the mode selected.

4. Disconnect the mode control motor connector at

each mode selected and check for continuity bet-

ween the motor terminals according to the table

below.

5. Replace the mode control motor if there is no con-

tinuity for any one mode selected.ProCarManuals.com

Recirculation Contro l Moto r
Replacemen t
1. Remov e th e blowe r uni t (se e pag e 22-67 )
2 . Remov e th e thre e screw s an d th e recirculatio n con -
tro l moto r cove r fro m th e blowe r unit .
RECIRCULATIO NCONTROL MOTO R COVE R
3. Remov e th e thre e screw s an d th e recirculatio n con -
trol motor .
RECIRCULATIO NCONTROL MOTO R
4. Instal l th e recirculatio n contro l moto r i n th e revers e
orde r o f removal. Then appl y batter y voltage , an d
watc h th e doo r movement .
• Mak e sur e tha t th e recirculatio n doo r move s
smoothl y withou t binding .
• Mak e sur e th e moto r doesn' t pul l th e doo r to o
far .
Tes t
Connec t batter y powe r t o th e No . 1 termina l of the
recirculatio n contro l motor , the n connec t groun d t o
th e No . 2 terminal ; th e recirculatio n contro l moto r
shoul d run , an d sto p a t REC .
I f i t doesn't , revers e th e connections ; th e recircula -
tion contro l moto r shoul d run , an d sto p a t FRE .
NOTE : I f th e recirculatio n contro l moto r doe s no t
run , remov e it , an d chec k th e recirculatio n contro l
linkag e an d doo r fo r smoot h movement . I f th e recir -
culatio n contro l linkag e an d doo r mov e smoothly ,
replac e th e recirculatio n contro l motor .
2 . Chec k fo r continuit y betwee n th e terminal s o f th e
recirculatio n contro l moto r accordin g t o th e table .
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Vent Doo r Contro l Moto r
Replacemen t
1. Remov e th e thre e screw s an d ven t doo r contro l
motor .
VENT DOO R CONTRO L
MOTOR
2. Instal l th e ven t doo r contro l moto r i n th e revers e
orde r o f removal . The n appl y batter y voltage , an d
watc h th e doo r move .
• Mak e sur e tha t th e ven t doo r move s smoothl y
withou t binding .
• Mak e sur e th e moto r doesn' t pul l th e ven t doo r
too far .
Tes t
1. Connec t batter y powe r t o th e No . 1 termina l o f th e
ven t doo r contro l motor , the n connec t groun d to th e
No . 2 terminal ; th e ven t doo r contro l moto r shoul d
run , an d sto p a t CLOSE .
I f i t doesn't , revers e th e connections ; th e ven t doo r
contro l moto r shoul d run , an d sto p a t OPEN .
NOTE : I f th e ven t doo r contro l moto r doe s no t run ,
remov e it , an d chec k th e ven t doo r contro l linkag e
an d doo r fo r smoot h movement . I f th e ven t doo r
contro l linkag e an d doo r mov e smoothly , replac e
th e ven t doo r contro l motor .
2 . Measur e resistanc e betwee n th e No . 3 termina l an d
No. 5 terminal , i t shoul d b e approx . 1 0
3 . Measur e resistanc e betwee n th e No . 3 termina l an d
No. 4 terminal , i t shoul d b e approx . 0. 6 a t OPE N
and approx . 9. 4 a t CLOSE .
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In-car Temperature Sensor
Removal
The in-car temperature sensor assembly includes a
small fan (aspirator fan) to draw air past the sensor (see
page 22-66('93-'96), 91('91-'92)).

SRS components are located in this area. Review the SRS

component locations, precautions, and procedures in the

SRS section (24) before performing repairs or service.

1. Remove the center console panel (see page 22-54).
2. Remove the two screws and the in-car temperature sensor from the under side of the center console

panel. Be careful not to damage the center console

panel.

IN-CAR TEMPERATURE

SENSOR

UNDER SIDE OF CENTER
CONSOLE PANEL
Test
Compare the resistance reading between the No, 1 and No. 2 terminals of the in-car temperature sensor with
specifications shown in the following graph: It should

be within specification.

TEMPERATURE

CAUTION: The sensor uses a thermistor which can
be damaged if high current is applied to it during test-
ing. Therefore, use a circuit tester that puts out a
measuring current of 1 mA or less.ProCarManuals.com

Outside Ai r Temperatur e Senso r
Remova l
Remove th e screw , disconnec t th e connector , an d
remov e th e outsid e ai r temperatur e sensor . B e carefu l
no t t o damag e th e fron t grill e an d fron t bumper .
OUTSIDE AI RTEMPERATUR ESENSOR
Test
Compar e th e resistanc e readin g betwee n th e terminal s
o f th e outsid e ai r temperatur e senso r wit h specifica -
tions show n in th e followin g graph : I t shoul d b e withi n
specification .
NOTE : Di p th e senso r i n ic e water , an d measur e th e
resistance . The n pou r ho t wate r o n th e sensor , an d
chec k fo r chang e i n resistance .
CAUTION : Th e senso r use s a thermisto r whic h
ca n b e damage d if hig h curren t i s applie d to it dur -
in g testing . Therefore , us e a circui t teste r tha t put s
out a measurin g curren t o f 1 m A o r less .
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Sunlight Sensor

Removal

With a small screwdriver, carefully pry the sunlight sen-

sor out of the dashboard and disconnect its connector.

Protect the dashboard; cover it with a shop towel before

you pry against it.

SUNLIGHT

SENSOR
Test

Measure the voltage between the terminals with the sen-

sor out of direct sunlight.

• With the connector connected (probe the back of it):

1.4 ± 0.2 V

• With the connector disconnected: 0.1 — 0.2 VProCarManuals.com

Heater Core Temperature Sensor

Removal

Disconnect the connector, remove the clamp and the

heater core temperature sensor.

CLAMP

HEATER CORE

TEMPERATURE

SENSOR
Compare the resistance reading between the terminals

of the heater core temperature sensor with specifica-

tions shown in the following graph: It should be within

specification.

NOTE: Dip the sensor in ice water, and measure the

resistance. Then pour hot water on the sensor, and

check for change in resistance.

CAUTION: The sensor uses a thermistor which

can be damaged if high current is applied to it

during testing. Therefore, use a circuit tester

that puts out a measuring current of 1 mA or

less.
TestProCarManuals.com