Terminal
Signal
1O
Water
temperature
sensor input
1P
A/C
1Q
Evaporator
temperature
sensor input
signal
1R
—
1S
Solar radiation
sensor input
1T
GND
1U
Potentiometer
signal
1V
—
CONTROL SYSTEM
Connected to
Test condition
Water temperature
Depends on temperature
sensor
surrounding sensor
Refrigerant
Fan switch at OFF
pressure switch
Fan switch at 1st
position, A/C switch ON
Evaporator
Depends on temperature
temperature sensor
surrounding sensor
—
Solar radiation
Incandescent light (60W)
sensor
shining on solar
radiation sensor from
distance of approx.
100mm {3.9 in}
Light to solar radiation
sensor block
Ground
Under any condition
Air mix actuator
Set temperature at MAX
COLD
Set temperature at MAX
HOT
—
Voltage (V)
See Figure
4
12
Below 1.0
See Figure
1
—
—
4.0
Below 1.0
Below 1.0
0.6
4.3
—
—
Action
• Inspect for continuity
(Climate control unit—water
temperature sensor: 1O—A,
1I—B)
• Inspect for short circuit
(Climate control unit—water
temperature sensor: 1O—A)
• Inspect water temperature
sensor
• Inspect terminal voltage of
climate control unit (2H, 2L)
• Inspect for continuity or
short circuit (Climate control
unit—refrigerant pressure
switch: 1P—A (Dual-
pressure type), 1P—C
(Triple-pressure type))
(Refrigerant pressure
switch—PCM: B—1AC)
• Inspect refrigerant pressure
switch
• Inspect PCM terminal
voltage (1AC)
(See
F–45 PCM
INSPECTION
)
• Inspect terminal voltage of
climate control unit (2H, 2L)
• Inspect for continuity
(Climate control unit—
evaporator temperature
sensor: 1Q—A, 1I—B)
• Inspect for short circuit
(Climate control unit—
evaporator temperature
sensor: 1Q—A)
• Inspect evaporator
temperature sensor
• Inspect terminal voltage of
climate control unit (2H, 2L)
—
• Inspect for continuity or
short circuit (Climate control
unit—solar radiation sensor:
1S—B, 1B—A)
• Inspect terminal voltage of
climate control unit (1B)
• Inspect solar radiation
sensor
• Inspect for continuity
(Climate control unit—
ground: 1T—GND)
• Inspect center panel
• Inspect for continuity or
short circuit (Climate control
unit—air mix actuator: 1U—
C)
• Inspect air mix actuator
• Inspect terminal voltage of
climate control unit (1B)
—
U–49
U