1999 NISSAN PICK-UP Repair Manual

A/C System
TROUBLE DIAGNOSIS PROCEDURE FOR A/C SYSTEM
SYMPTOM:
lA/C system does not come on.
Inspection flow
*1: HA-2046 *2: HA-2041 *3: HA-2046
COMPONENT DESCRIPTION
Automatic amplifier (Auto amp.)
The auto amplifier has a built-in microcomputer which processes
information sent from various sensors needed for air conditioner
operation. The air mix door motor, mode door motor, intake door
motor, blower motor and compressor are then controlled.
The auto amplifier is unitized with control mechanisms. Signals
from various switches and Potentio Temperature Control (PTC)
are directly entered into auto amplifier.
Self-diagnostic functions are also built into auto amplifier to pro-
vide quick check of malfunctions in the auto air conditioner sys-
tem.
Potentio temperature control (PTC)
The PTC is built into the A/C auto amp. It can be set at an inter-
val of 1ÉC in the 18ÉC to 32ÉC temperature range by turning the
temperature dial. The set temperature is digitally displayed.
SHA354F
RHA470H
TROUBLE DIAGNOSESAUTO
HA-2045

MAIN POWER SUPPLY AND GROUND CIRCUIT
CHECK
Power Supply Circuit Check
Check power supply circuit for air conditioner system.
Refer to EL section (ªWiring Diagramº, ªPOWER SUPPLY
ROUTINGº).
DIAGNOSTIC PROCEDURE
SYMPTOM: A/C system does not come on.
Auto amp. check
Check power supply circuit for auto amp. with ignition switch ON.
Measure voltage across terminal Nos.
V1,V2,V20and body
ground.
Voltmeter terminal
Voltage
Å@
V1
Body ground Approx. 12VV2
V20
RHA632G
RHA633GA
TROUBLE DIAGNOSESAUTO
A/C System (Cont'd)
HA-2046

Mode Door Motor
TROUBLE DIAGNOSIS PROCEDURE FOR MODE DOOR MOTOR
SYMPTOM:
lAir outlet does not change.
lMode door motor does not operate normally.
Inspection flow
*1: HA-15 in D22 Service
Manual, Publication No.
SM7E-0D22G1
*2: HA-2041
*3: HA-2035
*4: HA-2036*5: HA-2037
*6: HA-2038
*7: HA-2081
*8: HA-2083
*9: HA-2085
*10: HA-2087*11: HA-2049
*12: HA-2036
*13: HA-2051
*14: HA-2041
*15: HA-2040
SHA343F
TROUBLE DIAGNOSESAUTO
HA-2047

SYSTEM DESCRIPTION
Component parts
Mode door control system components are:
1) Auto amplifier
2) Mode door motor
3) In-vehicle sensor4) Ambient sensor
5) Sunload sensor
6) Intake sensor
System operation
The auto amplifier computes the air outlet conditions according to the ambient temperature and the in-ve-
hicle temperature. The computed outlet conditions are then corrected for sunload to determine air outlet
through which air is discharged into the passenger compartment.
Mode door control specification
COMPONENT DESCRIPTION
The mode door motor is attached to the heater unit. It rotates so
that air is discharged from the outlet set by the auto amplifier.
Motor rotation is conveyed to a link which activates the mode
door.
RHA471H
RHA384H
RHA472H
TROUBLE DIAGNOSESAUTO
Mode Door Motor (Cont'd)
HA-2048

DIAGNOSTIC PROCEDURE
SYMPTOM: Mode door motor does not operate normally.
CHECK MODE DOOR MOTOR POSI-
TION SWITCH.
1. Set up code No.
in Self-diagnosis
STEP 4.
2. Disconnect auto amp. harness connec-
tor after turning ignition switch OFF.
3. Check if continuity exists between ter-
minal Nos.
V29,V31of auto amp. har-
ness connector and body ground.
4. Using above procedure, check for conti-
nuity in other modes, as indicated in
chart.
OK
cNG
Disconnect mode door
motor harness connector.
Note
CHECK BODY GROUND
CIRCUIT FOR MODE
DOOR MOTOR.
Does continuity exist
between mode door motor
harness terminal No.
V17
and body ground?
Yes
Reconnect auto amp. har-
ness connector.
CHECK POWER SUPPLY
FOR MODE DOOR
MOTOR CONTROL CIR-
CUIT.
Do approx. 5 volts exist
between mode door motor
harness terminals and body
ground?
Yes No INSPECTION END
Reconnect
mode door
motor har-
ness con-
nector.
VAVB
(Go to next page.)
Code No.Condi-
tionTerminal No.
Conti-
nuityÅ@
VENTV29orV31
Body
groundYesorB/LV29orV30
FOOTV30orV31
D/FV31orV32
DEFV30orV32
Terminal No.
Voltage
Å@
V1
Body
groundApprox. 5VV2
V3
V4
V5
V6
Note:
If the result is NG or No after checking circuit continuity, repair harness
or connector.
RHA473H
RHA474H
RHA475H
RHA476H
.
.
.
.
.
..
TROUBLE DIAGNOSESAUTO
Mode Door Motor (Cont'd)
HA-2049

VAVB
Note
CHECK MODE DOOR MOTOR POSITION
SWITCH.
Set up Self-diagnosis STEP 4.
Measure voltage across auto amp. har-
ness terminals and body ground.
OK NGCheck circuit continuity
between each terminal on
auto amp. and on mode
door motor.
If OK, check harness for
short.
OK
Replace auto amp.
Replace mode door
motor.
CHECK FOR OUTPUT OF AUTO AMP.
Do approx. 10.5 volts exist between auto
amp. harness terminals No.
V15andV16
when code No. is switched from ªºto
ª
º or when code No. is switched from
ª
ºtoªº?
Yes
cNo
Replace auto amp.
Replace mode door motor.
Note:
If the result is NG or No after checking circuit continuity, repair harness
or connector.
Code No.Condi-
tionTerminal No.
@Å
V29V30V31V32
VENT 0V 5V 0V 5V
Body
ground
orB/L 0V 0V 5V 5V
FOOT 5V 0V 0V 5V
D/F 5V 5V 0V 0V
DEF 5V 0V 5V 0V
0V: Approx. 0V
5V: Approx. 5V
Terminal No.
Conti-
nuity
Å@
Auto
amp.Mode door
motor
Yes
V29V2
V30V3orV6
V31V1orV4
V32V5
Code No.Mode
door
motor
operationTerminal
No.Voltage
V
V15V16
®VENT®
B/LÅ@
Approx.
10.5
®DEF®
VENT@Å
þ Stop þ þ 0
RHA477H
RHA478H
RHA479H
..
.
.
.
.
TROUBLE DIAGNOSESAUTO
Mode Door Motor (Cont'd)
HA-2050

COMPONENT INSPECTION
Mode door motor
Terminal No.
Mode door operation Direction of side link rotation
V8V7
Å@VENT®DEF Counterclockwise
þ þ STOP STOP
@
ÅDEF®VENT Clockwise
CONTROL LINKAGE ADJUSTMENT
Mode door
1. Install mode door motor on heater unit and connect it to main
harness.
2. Set up code No.
in Self-diagnosis STEP 4. Refer to
HA-2038.
3. Move side link by hand and hold mode door in DEF mode.
4. Make sure mode door operates properly when changing from
code No.
toby pushing DEF switch.
VENT B/L B/L FOOT D/F DEF
RHA480H
RHA481H
RHA472H
TROUBLE DIAGNOSESAUTO
Mode Door Motor (Cont'd)
HA-2051

Air Mix Door Motor
TROUBLE DIAGNOSIS PROCEDURE FOR AIR MIX DOOR
SYMPTOM:
lDischarge air temperature does not change.
lAir mix door motor does not operate.
Inspection flow
*1: HA-2035
*2: HA-2036
*3: HA-2038
*4: HA-2081*5: HA-2083
*6: HA-2085
*7: HA-2087
*8: HA-2055*9: HA-2040
*10: HA-2055
*11: HA-2057
*12: HA-2041
SHA338F
TROUBLE DIAGNOSESAUTO
HA-2052