Lexus SC300 / Lexus SC400. Service manual — part 949

SENSOR INSPECTION FOR AIR CONDITIONING SYSTEM – AC005-04

December 16, 2004

Page 9 of 12

Procedure B:

a. Disconnect the solar

sensor connector.

b. Measure the resistance between

terminals 2 and 3 of the solar
sensor under the
following conditions:

S

Cover the sensor with a cloth
to avoid direct light.

S

Expose the sensor to light
from a distance of 300 mm
(11.81 in.) or less with an
inspection light.

NOTE:

When using an analog tester, connect
the positive (+) lead to terminal 3 and
negative (–) lead to terminal 2 of the
solar sensor.

HINT:

If the light is weak, the sensor may not react. Be sure to use an incandescent light for
an inspection light.

Standard:

CONDITION

SPECIFICATION

When the sensor is covered with a cloth

(to avoid direct light)

Infinite ohms

When the sensor is exposed to light

Less than infinite resistance

Inspection

Procedure

(Continued)

Lock

SENSOR INSPECTION FOR AIR CONDITIONING SYSTEM – AC005-04

December 16, 2004

Page 10 of 12

Procedure C:

a. Turn the ignition switch ON.

b. Measure the voltage between

terminals TSR (+) and CLTE (–)
of the connector under the
following conditions:

S

Cover the sensor with a cloth
to avoid direct light.

S

Expose the sensor to light
from a distance of 300 mm
(11.81 in.) or less with an
inspection light.

HINT:

S

If the light is weak, the sensor may not react. Be sure to use an incandescent light
for an inspection light.

S

Do not disconnect the solar sensor connector.

Standard:

CONDITION

SPECIFICATION

When the sensor is covered with a cloth

(to avoid direct light)

Below 0.8 V

When the sensor is exposed to light

4.3 +/– 0.3 V

c. Measure the voltage between

terminals TSL (+) and CLTE (–)
of the connector under the
following conditions:

S

Cover the sensor with a cloth
to avoid direct light.

S

Expose the sensor to light
from a distance of 300 mm
(11.81 in.) or less with an
inspection light.

HINT:

S

If the light is weak, the sensor may not react. Be sure to use an incandescent light
for an inspection light.

S

Do not disconnect the solar sensor connector.

Standard:

CONDITION

SPECIFICATION

When the sensor is covered with a cloth

(to avoid direct light)

Below 0.8 V

When the sensor is exposed to light

4.3 +/– 0.3 V

Inspection

Procedure

(Continued)

CLTE

TSR

TSL

CLTE

SENSOR INSPECTION FOR AIR CONDITIONING SYSTEM – AC005-04

December 16, 2004

Page 11 of 12

Procedure D:

a. Turn the ignition switch ON.

b. Using the tester, measure the

voltage between terminals
TSD (+) and CLTE (–) of the
connector under the
following conditions:

S

Cover the sensor with a cloth
to avoid direct light.

S

Expose the sensor to light
from a distance of 300 mm
(11.81 in.) or less with an
inspection light.

HINT:

S

If the light is weak, the sensor may not react. Be sure to use an incandescent light
for an inspection light.

S

Do not disconnect the solar sensor connector.

Standard:

CONDITION

SPECIFICATION

When the sensor is covered with a cloth

(to avoid direct light)

Below 0.8 V

When the sensor is exposed to light

4.3 +/– 0.3 V

Inspection

Procedure

(Continued)

TSD

CLTE

SENSOR INSPECTION FOR AIR CONDITIONING SYSTEM – AC005-04

December 16, 2004

Page 12 of 12

6. Inspect Room Humidity Sensor.

Measure the humidity and output
voltage of the humidity sensor when
the sensor is installed on the vehicle
and the temperature at the humidity
sensor position (room temperature
sensor position) is 77

°

F (25

°

C).

If the output voltage is within the
specifications according to the graph
and table below, the sensor is normal.

HINT:

For the inspection procedure of the
room temperature sensor, refer to
“Room Temperature Sensor Inspection
Procedure” in this bulletin.

A. Turn the ignition switch to the

ON position.

B. Measure the voltage between

terminal VO (3) and GND (2) of
the room humidity sensor.

C. Measure the humidity and voltage

when the room temperature
(humidity sensor position) is 77

°

F

(25

°

C). According to the result,

determine whether the sensor is
normal or not.

HUMIDITY (% RH)

OUTPUT VOLTAGE

AT 77

°

F (25

°

C)

10

0.70 to 1.08 V

20

0.72 to 1.57 V

30

1.13 to 1.95 V

40

1.61 to 2.24 V

50

1.99 to 2.46 V

60

2.26 to 2.66 V

70

2.48 to 2.85 V

80

2.68 to 3.04 V

90

2.87 to 3.05 V

Inspection

Procedure

(Continued)

VO

GND

Resistance
k

Ω

3.50

3.00

2.50

2.00

1.50

1.00

0.50

0.00

32

(0)

68

(20)

104

(40)

140

(60)

Temperature

°

F (

°

C)

Max

Min

176

(80)

212

(100)