Page 905 of 1226
Intake door control speci®cation
COMPONENT DESCRIPTION
The intake door motor is attached to the intake unit. It rotates so
that air is drawn from inlets set by the auto ampli®er. Motor rota-
tion is conveyed to a lever which activates the intake door.
CONTROL LINKAGE ADJUSTMENT
Intake door
1. Install intake door motor on intake unit and connect it to main
harness.
2. Set up code No.
in Self-diagnosis STEP 4. Refer to HA-67.
3. Move intake door link by hand and hold it in REC position.
4. Attach intake door lever to rod holder.
5. Make sure intake door operates properly when changing from
code No.
toby pushing DEF switch.
REC 20% FRE FRE
RHA692G
RHA593F
TROUBLE DIAGNOSESAUTO
Intake Door Motor (Cont'd)
HA-84
Page 906 of 1226

DIAGNOSTIC PROCEDURE
SYMPTOM: Intake door motor does not operate normally.
+Perform Self-diagnosis STEP 4 before referring to the ¯ow
chart.
CHECK POWER SUPPLY FOR INTAKE
DOOR MOTOR.
Disconnect intake door motor harness
connector.
Do approx. 12 volts exist between intake
door motor harness terminal No.j
1and
body ground?
Ye s
cNo
Check power supply circuit
and 10A fuse (No.
6,
located in the fuse block).
Note
CHECK FOR AUTO AMP. OUTPUT.
Set up Self-diagnosis STEP 4.
Measure voltage across auto amp. har-
ness terminals and body ground.
OK
cNG
Check circuit continuity
between each terminal on
auto amp. and on intake
door motor.
OK
Replace auto amp.
Replace intake door motor.
Note:If the result is NG or No after checking circuit continuity, repair harness or
connector.
Code No.Terminal No.
ConditionVoltage
VÅ@
j13
Body
groundREC0
j
2312
j
1412j1320%
FRE12
j230
j
1412j13
FRE12
j2312
j
140
0V: Approx. 0V
12V: Approx. 12V
Terminal No.
Continu-
ityÅ@
Auto amp.Intake door
motor
j
13j13
Ye s j23j23j14j14
SHA858EB
RHA081GB
RHA642G
RHA634G
.
.
.
TROUBLE DIAGNOSESAUTO
Intake Door Motor (Cont'd)
HA-85
Page 907 of 1226
Blower Motor
TROUBLE DIAGNOSIS PROCEDURE FOR BLOWER MOTOR
SYMPTOM:
+Blower motor operation is malfunctioning.
+Blower motor operation is malfunctioning under out of starting fan speed control.
Inspection ¯ow
*1: HA-64
*2: HA-65
*3: HA-67
*4: HA-89*5: HA-103
*6: HA-105
*7: HA-107
*8: HA-110*9: HA-79
*10: HA-70
*11: HA-69
SHA026F
TROUBLE DIAGNOSESAUTO
HA-86
Page 908 of 1226

SYSTEM DESCRIPTION
Component parts
Fan speed control system components are:
1) Auto amp.
2) Fan control amp.
3) A/C LAN system (PBR built in mode door motor and air mix door motor)
4) In-vehicle sensor
5) Ambient sensor
6) Sunload sensor
7) Intake sensor
System operation
Automatic mode
In the automatic mode, the blower motor speed is calculated by the automatic ampli®er based on inputs from
the PBR, in-vehicle sensor, sunload sensor, intake sensor and ambient sensor. The blower motor applied
voltage ranges from approximately 5 volts (lowest speed) to 12 volts (highest speed).
The control blower speed (in the range of 5 to 12V), the automatic ampli®er supplies a gate voltage to the fan
control ampli®er. Based on this voltage, the fan control ampli®er controls the voltage supplied to the blower
motor.
Starting fan speed control
Start up from ``COLD SOAK'' condition (Automatic mode)
In a cold start up condition where the engine coolant temperature is below 50ÉC, the blower will not operate
for a short period of time (up to 150 seconds). The exact start delay time varies depending on the ambient
and engine coolant temperature.
In the most extreme case (very low ambient) the blower starting delay will be 150 seconds as described above.
After this delay, the blower will operate at low speed until the engine coolant temperature rises above 55ÉC,
at which time the blower speed will increase to the objective speed.
Start up from normal or ``HOT SOAK'' condition (Automatic mode)
The blower will begin operation momentarily after the AUTO button is pushed. The blower speed will gradu-
ally rise to the objective speed over a time period of 3 seconds or less (actual time depends on the objective
blower speed).
SHA006FB
TROUBLE DIAGNOSESAUTO
Blower Motor (Cont'd)
HA-87
Page 909 of 1226

Blower speed compensation
Sunload
When the in-vehicle temperature and the set temperature are very close, the blower will be operating at low
speed. The low speed will vary depending on the sunload. During conditions of high sunload, the blower low
speed is ``normal'' low speed (approx. 6V). During low or no sunload conditions, the low speed will drop to
``low'' low speed (approx. 5V).
Ambient
When the ambient temperature is in the ``moderate'' range [10 þ 15ÉC], the computed blower voltage will be
compensated (reduced) by up to 3.5V (depending on the blower speed). In the ``extreme'' ambient ranges
[below 0ÉC and above 20ÉC] the computed objective blower voltage is not compensated at all. In the ambi-
ent temperature ranges between ``moderate'' and ``extreme'' [0 - 10ÉC and 15 - 20ÉC], the amount of compen-
sation (for a given blower speed) varies depending on the ambient temperature.
Fan speed control speci®cation
COMPONENT DESCRIPTION
Fan control ampli®er
The fan control ampli®er is located on the cooling unit. The fan
control amp. receives a gate voltage from the auto amp. to step-
lessly maintain the blower fan motor voltage in the 5 to 12 volt
range (approx.).
RHA694G
RHA695G
TROUBLE DIAGNOSESAUTO
Blower Motor (Cont'd)
HA-88
Page 910 of 1226

DIAGNOSTIC PROCEDURE
SYMPTOM: Blower motor operation is malfunctioning under
Starting Fan Speed Control.
CHECK POWER SUPPLY FOR FAN
CONTROL AMP.
Disconnect fan control amp. harness con-
nector.
Do approx. 12 volts exist between fan
control amp. harness terminal No.j
1and
body ground?
Ye s
cNo
CHECK POWER SUPPLY
FOR BLOWER MOTOR.
Disconnect blower motor
harness connector.
Do approx. 12 volts exist
between blower motor har-
ness terminal No.j
2and
body ground?
No
.
Ye s
Note
CHECK BODY GROUND CIRCUIT FOR
FAN CONTROL AMP.
Does continuity exist between fan control
amp. harness terminal No.j
3and body
ground?
Ye sCheck
power sup-
ply circuit
and 15A
fuses (No.1and2,
located in
the fuse
block).
Note
Reconnect fan control amp. harness con-
nector.
Check circuit continuity
between blower motor har-
ness terminal No.j
1and
fan control amp. harness
terminal No.j
1.
OK
CHECK FOR AUTO AMP. OUTPUT.
Set up Self-diagnosis STEP 4.
Measure voltage across fan control amp.
harness terminal No.j
2and body ground.
OKCHECK BLOWER
MOTOR.
(Refer to HA-91.)
NG
Replace blower motor.
cNG
jA(Go to next page.)
Replace fan control amp.
Note:If the result is NG or No after checking circuit continuity, repair harness or
connector.
Code No.Terminal No.
VoltageÅ@
þj2Body groundApprox.
2.5-3VApprox.
9 - 10V
RHA087GB
RHA643G
RHA644G
RHA645G
RHA646G
..
.
..
.
.
TROUBLE DIAGNOSESAUTO
Blower Motor (Cont'd)
HA-89
Page 911 of 1226

jA
Disconnect auto amp. and fan control amp.
harness connector.
Note
Does continuity exist between auto amp.
harness terminal No.j
17and fan control
amp. harness terminal No.j
2?
Continuity should exist.
If OK, check harness for short.
Ye s
CHECK FAN FEED BACK CIRCUIT.
Do approx. 12 volts exist between auto
amp. harness terminal No.j
20and body
ground?
Ye s
cNo
Check power supply circuit
and 15A fuses (No.
1
and2, located in the fuse
block).
Refer to EL section (``Wiring
Diagram'', ``POWER SUP-
PLY ROUTING'').
Note
Do approx. 12 volts exist between auto
amp. harness terminal No.j
18and body
ground?
Ye s
cNo
Check circuit continuity
between blower motor har-
ness terminal No.j
1and
auto amp. harness terminal
No.j
18.
Continuity should exist.
If OK, check harness for
short.
Replace auto amp.
Note:
If the result is NG or No after checking circuit continuity, repair harness
or connector.
RHA647G
RHA648G
RHA649G
RHA650G
RHA651G
.
.
.
.
.
TROUBLE DIAGNOSESAUTO
Blower Motor (Cont'd)
HA-90
Page 912 of 1226
COMPONENT INSPECTION
Blower motor
Con®rm smooth rotation of the blower motor.
+Ensure that there are no foreign particles inside the intake unit.
RHA941F
TROUBLE DIAGNOSESAUTO
Blower Motor (Cont'd)
HA-91