air conditioning NISSAN PULSAR 1987 User Guide

74 Cooling and Heating Systems
NOTE: Refer to the Fuel and Engine Man-
agement section for the correct procedure for
backprobing the control unit.

(3) In operation (1) if the cooling fan is station-
ary proceed as follows:

(a) Connect a jumper lead between the terminals
A and B of the diagnostic link connector. (b) if the fan runs, the fan circuit is satisfactory.
If the engine is overheating check the coolant temper-
ature sensor as described in the Fuel and Engine
Management section under the appropriate codes. (c) If the fan does not run, check the fuse (6) and
the fusible link (4) show n on the illustration.
(d) Backprobe terminal C1 at the electronic
control unit using an LED t est lamp connected to the
positive battery terminal. If no circuit exists, renew
the electronic control unit. (e) If the fuse and fusible links are serviceable,
ensure that power is available at the white and pink
wires from the fuse and fusible link of the cooling fan
relay. Repair any faults in the wiring to that point if
necessary. (f) Switch the ignition Off. disconnect the
cooling fan wiring connector at the radiator and
connect power to the fan. Renew the fan if it does not
run.

(4) On air conditioned models, remove the
jumper lead from the ALDL connector if still in-
stalled, start the engine and allow it to idle. Switch the
air conditioning on and ensu re that the cooling fan
runs.

If the cooling fan is opera ting as described above
but cooling system problems still exist, refer to the
Trouble Shooting heading at the start of this section.

TO REMOVE AND INSTAL COOLING FAN
(1) Disconnect the negative battery terminal.
(2) Disconnect the cooling fa n and, if applicable,
the air conditioning fan wiring connectors at the
upper edge of the radiator. (3) On models with air conditioning, remove the
compressor hose bracket bolt from the centre of the
radiator support panel.

Dismantled view of the fans and the shroud assembly. Air conditioned model.

Cooling and Heating Systems 75
(4) Remove the bolts retaining the fan shroud
assembly to the radiator and carefully move the
shroud assembly upwards and towards the engine to
release it from the lower mountings.

NOTE: On models with air conditioning, it
will be necessary to hold the air conditioning
compressor hoses toward s the engine to
allow clearance for removal of the shroud
assembly.

(5) If necessary, remove the fan from the fan
motor by removing the retaining bolts or on some
models the nut and washers.
(6) If necessary, remove the fan motor from the
shroud assembly by removing the retaining bolts or
nuts. Installation is a reversal of the removal procedure
with attention to the following points:

(1) Ensure all the fan motor and fan retaining
nuts and bolts are tightened securely. (2) Ensure that all the rubber mountings are in
good condition. Installation is a reversal of the removal procedure
with attention to the following points:

(1) Ensure that all sealing surfaces are clean.
(2) Renew the O ring on installation.
(3) Tighten the thermostat cover retaining bolts
securely.
(4) Fill the cooling system as previously de-
scribed ensuring that the heater control lever is in the
maximum heat position. Check for coolant leaks.
TO CHECK

NOTE: A visual examination of the thermo-
stat will often determine its serviceability
and make further testing unnecessary. For
instance, a thermostat with its valve fully-
open when removed from a cold engine is
obviously faulty and should be renewed.

Remove the thermostat from the thermostat
6. THERMOSTAT
Special Equipment Required:
To Check — Thermometer

TO REMOVE AND INSTAL
(1) Drain the cooling system as previously de-
scribed under the Radiator heading.
(2) On 1.6 liter models, remove the air cleaner
assembly. Refer to the Fuel and Engine Management
section if necessary. (3) Disconnect the top radiator hose from the
thermostat cover.
(4) Remove the bolts retaining the thermostat
cover to the thermostat housing. (5) Remove the thermostat cover, thermostat
and O ring from the thermostat housing.
NOTE: The thermostat and cover are ser-
viced as a unit and cannot be renewed
separately.


View of the thermostat removed from the vehicle and dismantled for testing. Line drawing showing the correct method to test the
thermostat.

(4) Progressively heat the mixture noting the
temperature reading on the thermometer as the ther-
mostat valve commences to open and when it is fully
open.

See the Specifications for opening and fully open
temperatures.

A thermostat which is not opening or is not open
at the specified temperatures should be renewed.

78 Cooling and Heating Systems
The air conditioner operates only when the engine
is running as the compressor is belt driven from the
engine.

Operating the air conditioner with the tempera-
ture control raised to a hot setting will produce
dehumidified hot air which is particularly useful for
demisting the vehicle glass.

Maximum cooling is achieved by operating the air
conditioner with the temperature control lowered
fully to the coldest setting . Operate the fan at high
speed when using the coldest temperature setting to
avoid forming ice on the evaporator.

TO REMOVE AND INSTAL HEATER UNIT
(1) Remove the dashboard as described in the
Body section. (2) Drain the cooling system as previously de-
scribed in this section. (3) Loosen the hose clamps and disconnect the
heater hoses from the heater pipes.
NOTE: If the heater hos es will not come off
the heater pipes, do not use excess force or
the heater core retaining strap will be dam-
aged. Cut the hoses from the heater pipes.

(4) Remove the steering column upper mount-
ing bolts. (5) Remove the steering column cross support
bolts and move the support towards the right hand
side of the vehicle. (6) Remove the centre support retaining bolts
and remove the centre support from the vehicle.
(7) Remove the demister duct and the right
hand side ventilator duct from the vehicle. (8) Disconnect the blower fan wiring connector
from the rear of the heater controls. (9) Remove the heater retaining bolts.
(10) On models with air conditioning, it will be
necessary to loosen the evaporator mounting bolts. (11) Working in the engine compartment, push
the heater pipe grommet through the bulkhead. (12) Maneuver the heater unit upwards slightly
and out from the bulkhead using care not to damage
the heater pipes. (13) To remove the heater core and tap assembly,
remove the screws from the retaining strap and slide
the heater core from the heater unit.
Installation is a reversal of the removal procedure
with attention to the following points:

(1 ) Before installing the heater unit to the

View of the heater unit with the dashboard, centr e support, demister duct and right hand ventilator
duct removed.

Cooling and Heating Systems
11. BLOWER FAN
TO REMOVE AND INSTAL
(1) Disconnect the negative battery terminal.
(2) Working below the glov e compartment, dis-
connect the wiring connector to the blower fan motor.
(3) Remove the bolts retaining the blower fan
motor and carefully lower the motor while disconnect-
ing the drain hose.

Installation is a reversal of the removal procedure
with attention to the following points:
( t ) Tighten all bolts securely.
(2) Check that the blow er fan operates correctly.

Dismantled view of the blower fan and associated
components.
12. AIR CONDITIONING
DESCRIPTION
The air conditioning system, when used in con-
junction with the heater, enables any reasonable tem-
perature to be achieved inside the vehicle. It can also
reduce the humidity of the incoming air, aiding
demisting even when cooling is not required.

The basic components of the air conditioning sys-
tem are an evaporator, co ndenser, compressor, re-
ceiver/dryer, expansion valve and pipes and hoses
carrying the refrigerant through the system. Various
subsidiary controls and sensors are also utilized to
protect the system against low or high pressure and
excessive temperature.

The refrigerant will boil at a very low tempera-
ture (-33 deg C) and therefore must be contained
under pressure. Escaping refrigerant can cause frost-
bite and eye damage and will produce a poisonous gas
when burnt. Also, if the system suffers a rapid loss of
refrigerant, oil from the compressor may be carried
out with the refrigerant. It is recommended that any
work requiring disconnection of the components be
referred to an au thorized dealer.

In the event of major repair s to the vehicle such as
engine removal, the compress or hoses are of sufficient


Schematic diagram of a typical air conditioning
system.
length to allow the compressor to be removed as the
engine is lowered from the engine compartment with-
out disturbing any refrigerant line connections.

If the operation of the air conditioning system is
in doubt, it is recommended that the vehicle be taken
to an authorized dealer for testing and repair.

TO CHECK REFRIGERANT CHARGE
(1) Start the engine and operate the air condi-
tioner on maximum cooling for a few minutes.
(2) Observe the flow of refrigerant through the
sight glass located at the top of the receiver/dryer. On
some models it may be necessary to use a mirror to
see the sight glass. (3) If the system is operating correctly, the sight
glass will be clear during the operation of the com-
pressor. Occasional bubbles may be seen when the
compressor cycles on and off during operation, but a
NUT j-
Bubbles in the sight glass when the air conditioner is
operating indicates a low refrigerant charge.

Cooling and Heating Systems 81
continuous stream of bubbles indicates that the refriger-
ant charge is low.

A large number of bubbles or foam indicates that
the refrigerant charge is very low.

No bubbles or the presen ce of oil streaks in the
sight glass indicate that the system is completely
empty.

NOTE: If the outside air temperature is
high, a certain number of bubbles may be
observed in the sight gl ass, even though the
system is fully charged.

If the system requires recharging, the vehicle
should be taken to an authorized dealer for evacu-
ation, leak testing and recharging.

Do not operate the system if it is known that the
refrigerant charge is low as damage may result.

MAINTENANCE
The air conditioning system requires l i t t l e main-
tenance other than the following. Where applicable,
refer to the Lubrication an d Maintenance section for
the recommended service intervals.

(1) Check the refrigerant charge level in the
receiver/dryer sight glass. Recharge the system as
necessary. It is considered normal for the system to
require periodic recharging. (2) Inspect the air conditioner pipes and hoses
for leaks, deterioration and alignment. Evidence of oil
leakage is an indication of refrigerant leakage. Repair
or renew as necessary.
(3) Inspect the evaporator drain tube and the
condenser cooling fins for blockage. Clean as neces-
sary.
(4) Check the drive belt for deterioration and for
correct tension. Refer to the Engine Tune-up section
for the correct procedure.
(5) Operate the system at least once a week for
approximately 15 minutes to keep the compressor
seals lubricated.

86 Fuel and Engine Management
other. The fuel pressure is maintained at a constant
pressure relevant to the manifold vacuum. A dispos-
able paper element fuel filter is mounted on the engine
bulkhead.

The amount of fuel injected is relevant to the time
the injector remains open. The basic time the injector
remains open is governed by the control unit which
uses information from the various sensors to give
optimum engine efficiency for given conditions.

The idle air control (IAC) valve controls the fast
idle speed during engine warm up and maintains the
basic idle speed at a set value by compensating for
loads such as air conditioning or the selection of Drive
on automatic transaxle models.

The throttle body assembly is mounted to the
inlet manifold and controls the amount of air entering
the engine by the action of the throttle valve.

Efficient operation of the EFI system depends on
accurate signals being receiv ed by the control unit and
controlled air flow beyond the throttle valve. There-
fore it is essential that all air, fuel and electrical
connections be clean and tight.

3. SERVICE PRECAUTIONS AND
PROCEDURES

Electronic ignition systems can produce danger-
ously high voltages in both the primary and secondary
circuits. For this reason, extreme care must be taken
when working on or near the ignition system.

Do not start the engine if the battery terminals are
not clean and tight.

Do not use the fast charge or boost settings on a
battery charger to start the engine.

Do not disconnect the battery terminals while the
engine is running.

Disconnect the battery terminals before charging
the battery.

Disconnect the negative ba ttery terminal before
working on the engine management system.

Do not subject the control unit to temperatures
above 80 deg C.

Ensure that all wiring connectors are clean and
tight.

Disconnect the battery terminals and the control
unit wiring connectors before attempting any welding
operations.

Do not direct a steam cleaning or pressure
washing nozzle at engine management components
when cleaning the engine.

Ensure that the ignition is Off prior to disconnect-
ing the battery terminals, fusible links or the control
unit wiring connectors.

TO CONNECT ELECTRICAL TEST
EQUIPMENT

NOTE: Some types of tachometers, timing
lights and ignition system analysers are not
compatible with this engine management
system and may result in incorrect readings.
It is therefore recommended that the man-
ufacturer of the lest equipment be consulted
before proceeding to use the equipment.

If a test procedure requires the use of a
test lamp or voltmeter, ensure that only the
specified instrument is used to prevent mis-
leading diagnosis.

MULTIMETER
It is essential that in all tests where voltage or
resistance is to be measur ed, a digital display multi-
meter with a minimum 10 megohms impedance be
used.


The correct method of backprobing the wiring connec-
tors. The meter test probe should be modified with a piece of thin wire as shown.
All meter readings are to be performed with the
component wiring connectors installed unless other-
wise instructed. This can be done by inserting the
meter test probes from the wiring harness side of the
connector or backprobing. If the test probes are not
thin, they should be modified by attaching a thin piece
of wire to the end, giving a fine point that will not
damage the connector. Ensure that the wire is making
good contact with the probe.

If sealing plugs or boots are removed from wiring
connectors to facilitate bac kprobing, ensure that they
are correctly installed at the conclusion of the test
procedure.

To identify wiring connector terminals refer to the
wiring circuit diagrams.

Test Lamp
To avoid damage to the electronic components
when testing, the use of an LED (light emitting diode)
test lamp is recommended.

Fuel and Engine Management 91
components, erase the self diagnosis memory as
described under the following heading.

(7) Repeat the self diagnosis test procedure and
ensure that code 12 is displayed.

To Erase Memory
(1) With the ignition Off, remove the fusible link
that is positioned third from the front of the fusible
link connecting block located at the rear of the
battery. (2) Install the fusible link after 10 seconds.

View showing the location of the fusible links.
TO CHECK AND ADJUST IGNITION TIMING
(1) Connect a timing light to the engine as
previously described under the Service Precautions
and Procedures heading.
(2) Start the engine and allow it to reach normal
operating temperature. (3) Connect a jumper lead between terminals A
and B on the diagnostic link connector. (4) With the engine idling at the specified speed,
check the ignition timing with the timing light.
The timing mark on the crankshaft pulley should
be aligned with the pointer on the inner liming belt
cover.

(5) If necessary, loosen the distributor body
retaining nuts and turn the distributor until the timing
marks are aligned. (6) Tighten the distributor body retaining nuts
and check that the timing is correct. (7) Remove the jumper lead from the diagnostic
link connector and disconnect the timing light from
the engine.
TO ADJUST BASE IDLE SPEED

NOTE: The idle speed is controlled by the
idle air control (IAC) valve and is not

adjustable. The throttle stop screw controls
the base idle speed a nd is factory set. The
following base idle speed adjustment should
only be performed if the throttle body has
been renewed, or if comprehensive testing of
related components indicates that adjust-
ment is required.

(1) Before adjusting the base idle speed perform
the following tests;

(a) Check the spark plug gaps, the high tension
leads and the ignition timin g as described previously
in the Engine Tune-up section.
(b) Check the air inlet syst em for leaks between
the throttle body and inlet manifold and the inlet
manifold and cylinder head.
NOTE; Any vacuum leaks will make the
engine idle faster than it should.

(c) Check that all wiring connectors and vacuum
hoses are securely connected. (d) Ensure that the transaxle is in Park or
Neutral. (e) Ensure that the air cleaner element is service-
able.

(2) On 1.6 liter engines, remove the air cleaner
assembly, disconnect the vacuum hose from the
throttle body and seal the vacuum hose fitting.
(3) Ensure that the throttle valve moves freely
and returns to the fully closed position when slowly
released. (4) Connect an accurate tachometer to the en-
gine as previously descri bed under the Service Pre-
cautions and Procedures heading.
(5) Start the engine and allow the engine to
warm up and the idle rpm to stabilize. Check that all
electrical accessories and the air conditioning, if
equipped, are turned off. (6) With the engine idling in Park or Neutral,
slowly disconnect the brake servo unit vacuum supply
hose from the inlet manifold. Allow the engine to run
for one minute.
Location of the base idle adjusting screw. 1.8 liter
engine.

Electrical System 221

Wiring diagram (WD3) for the fan switch, blower, air conditioning, rear demister and power
window circuits.
COLOUR CODE
The first letter of tha code
represents the main wire color,
the other letters represent the
trace colours.
B - BLACK
L - BLUE
G - GREEN
R - BED
Y - YELLOW
W - WHITE
N - BROWN
0 - ORANGE
K - PINK
S - GREY
V - VIOLET
P - PURPLE
X - LIGHT GREEN
Z - LIGHT BLUE
M - DARK GREEN
T - DARK BLUE
A - LIGHT BROWN
E - SLATE
D - TAN KEY

1. Blower fan motor
2. To No. 11 WD5
3. Resistors
4. Blower fan switch
5. To ECU C2
6. Air conditioning switch
7. Thermo amplifier
8. Pressure switch
9. Air conditioning relay No. 2
10. Compressor
11. Air conditioning relay No. 1
12. To ECU B8
13. Air conditioning relav No. 3
14. Condenser fan
15. Cooling Ian relay
16. Fuse 22 BATT
17. Fuse 10 Ignition
18. To ECU C1
19. Rear demister switch
20. Cooling fan motor
21. Rear demister
22. Rear demister warning lamp
23. Power window relay
24. Circuit breaker
25. R H front power
window motor
26. Power window amplifier
27. R H front power window switch
28. Door lock switch
29. Main power window switch
30. L H front power
window switch
31. R H rear power window switch
32. L H rear power window switch
33. L H front power
window motor
34. R H rear power window motor
35. L H rear power window motor