climate control ACURA NSX 1997 Service Repair Manual

Radiator

Engine Coolant Refilling and Bleeding

CAUTION: When pouring engine coolant, be sure to

shut the relay box lid and not let coolant spill on the

electrical parts or the paint. If any coolant spills, rinse it

off immediately.

NOTE:

• Perform this maintenance when the engine is cool.

• Before replacing the coolant, turn the ignition ON,

slowly turn the climate control temperature knob to

90° and turn off the ignition. This will allow the

coolant in the heater to drain out with the rest of the

system.
1. Open the hood, the rear window and the engine

cover.

2. Remove the cover protecting the water pipes and

shift cables on the underside of the car.

3. Before removing the expansion tank cap, first

loosen the cap to lower pressure.

CAUTION: Do not remove the expansion tank cap

when engine is hot. The coolant is under pressure

and may blow out and scald you. Open the cap

slowly when the engine is cool.

4. Loosen the drain plug in the bottom of the radiator,

and drain the coolant.

5. Remove the two drain bolts from the water pipes,

and drain the coolant.

DRAIN BOLTS

15 N-m (1.5 kgf-m, 11 Ibf-ft)
DRAIN HOLE
DRAIN PLUG

WASHERS

Replace.ProCarManuals.com

Engine Coolant Refilling and Bleeding

CAUTION: When pouring engine coolant, be sure to

shut the relay box lid and not let coolant spill on the

electrical parts or the paint. If any coolant spills, rinse it

off immediately.

NOTE:

• Perform this maintenance when the engine is cool.

• Before replacing the coolant, turn the ignition ON,

slowly turn the climate control temperature knob to

90° and turn off the ignition. This will allow the

coolant in the heater to drain out with the rest of the

system.
1. Open the hood, the rear window and the engine

cover.

2. Remove the cover protecting the water pipes and

shift cables on the underside of the car.

3. Before removing the expansion tank cap, first

loosen the cap to lower pressure.

CAUTION: Do not remove the expansion tank cap

when engine is hot. The coolant is under pressure

and may blow out and scald you. Open the cap

slowly when the engine is cool.

4. Loosen the drain plug in the bottom of the radiator,

and drain the coolant.

5. Remove the two drain bolts from the water pipes,

and drain the coolant.

WASHERS

Replace.

DRAIN BOLTS

15 N-m (1.5 kgf-m, 11 Ibf-ft)
DRAIN HOLE
DRAIN PLUGProCarManuals.com

Climate control unit, stereo cassette/radio and glove box removal:

Disassemble in numbered sequence.

NOTE: Remove the center console panel.

CLIMATE CONTROL

UNIT

Disconnect the connectors.

SRS UNIT

Passenger's:
STEREO

CASSETTE RADIO

Disconnect the connectors.

GROUND CABLE

GLOVE BOX
Disconnect the connectors.

TRUNK LID OPENER

MAIN SWITCH
PASSENGER'S

AIRBAG

DLC

CONNECTOR

GLOVE BOX

LID

DASHBOARD LOWER

COVER (Passenger's)

Installation is the reverse of the removal procedure.

NOTE: Make sure the connectors are connected properly.

(cont'd)ProCarManuals.com

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

Climate Control Unit Input/Output Signals

CLIMATE

CONTROL UNIT

View from wire sideProCarManuals.com

5. Remove the three screws and center console

panel, then disconnect the 3P connector and 4P

connector from the floor wire harness.

CENTER CONSOLE PANEL

6. Remove the four screws, then disconnect the 14P

and 30P connectors from the automatic climate

control unit and remove it.

CLIMATE

CONTROL UNIT

UP CONNECTOR
30P CONNECTOR

7. Install in the reverse order removal.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

Relay and Control Unit Locations

Dashboard

IMMOBILIZER CONTROL UNIT
CLIMATE CONTROL UNIT

TURN SIGNAL/HAZARD

RELAY

DASHBOARD

LOWER COVER

INTEGRATED

CONTROL UNIT

UNDER-DASH FUSE BOXProCarManuals.com

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

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