Lexus ES300 (1997 year). Service manual - part 449

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

DI–573

725

1997 LEXUS ES300   (RM511U)

8

Check voltage between terminal ACT of ECM connector and body ground
(See page 

IN–27

).

NG

Check and replace ECM.

OK

9

Check harness and connector between A/C control assembly and ECM
(See page 

IN–27

).

NG

Repair or replace harness or connector.

OK

Proceed to next circuit inspection shown on
matrix chart  (See page 

DI–535

).

I00359

FACE

B/L

FOOT

F/D

DEF

L–W

L

L–R

B–L

L–O

4

5

6

7

8

1

2

J21

J20

From HEATER Fuse

Air Outlet Control
Servomotor

B

B

J/C

A/C Control Assembly

W–B

J/C

J15

A

A

II

W–B

4

A13

17

18

19

20

A13

A13

A13

A13

Display Code

Air Flow Mode

0 – 4

5

6 – 7

8

9

FACE

BI–LEVEL

FOOT

FOOT DEF

DEF

DI–574

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

726

1997 LEXUS ES300   (RM511U)

Air Outlet Control Servomotor Circuit

CIRCUIT DESCRIPTION

This circuit turns the servomotor and changes each mode damper position by signals from the A/C control
assembly. When the AUTO switch is ON, the A/C control assembly changes the mode automatically be-
tween FACE, BI–LEVEL. and FOOT according to the temperature setting.

WIRING DIAGRAM

INSPECTION PROCEDURE

1

Actuator check.

PREPARATION:
(a)

Set to the actuator check mode (See page 

DI–528

).

(b)

Press the DEF switch and change to step operation.

CHECK:
Press the DEF switch in order and check the condition of air flow
mode.
OK:

The mode changes with the change in the tempera-
ture displaly as shown in the table.

OK

Proceed to next circuit inspeciton shown on
matrix chart (See page 

DI–535

).

NG

DI0DK–01

I00357

FACE

B–L

FOOT

F/D

DEF

1

3
4
5

6

7

8

2

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

DI–575

727

1997 LEXUS ES300   (RM511U)

2

Check air outlet control servomotor.

PREPARATION:
Remove air outlet control servomotor (See page 

AC–76

).

CHECK:
(a)

Connect positive (+) lead to teminal 2 and negative (–)
lead to terminal 1.

(b)

Check the lever operation when the negaitive (–) lead is
connected to the teminals shown below.

OK:

The lever moves smoothly to the position for each
mode.

Ground Terminals

Mode

4

FACE

5

BI–LEVEL

6

FOOT

7

FOOT DEF

8

DEF

NG

Replace air outlet control servomotor.

OK

3

Check harness and connector between A/C control assembly and air outlet con-
trol servomotor, air outlet control servomotor and battery, ari outlet control ser-
vomotor and body ground (See page 

IN–27

).

NG

Repair or replace harness or connector.

OK

Repair or replace A/C control assembly.

I00355

A/C Control Assembly

IG

A13

26

GND

A13

14

J/C

J15

A

A

Battery

MAIN FL

ALT
100 A

B–R

J21

B

J20

B J/C

1K

1R

1

3

HEATER

B–Y

Ignition Switch

4

2

W

1K

1B

1

2

AM1

F10

F5

1

1

II

BE3840

I00356

I00372

ON

GND(–)

IG(+)

DI–576

–

DIAGNOSTICS

AIR CONDITIONING SYSTEM

728

1997 LEXUS ES300   (RM511U)

IG Power Source Circuit

CIRCUIT DESCRIPTION

This is the power source for the A/C control assembly (contains the ECU) and servomotors, etc.

WIRING DIAGRAM

INSPECTION PROCEDURE

1

Check voltage between terminals IG and GND of A/C control assembly connec-
tor.

PREPARATION:
(a)

Remove fromt ash receptacle (See page 

BO–79

).

(b)

Remove A/C control assembly with connectors still con-
nected (See page 

BO–79

).

(c)

Turn ignition switch ON.

CHECK:
Measure voltage between terminals IG and GND of A/C control
assembly.
OK:

Voltage: 10 – 14 V

OK

Proceed to next circuit inspection shown on
matrix chart (See page 

DI–535

).

NG

DI0DL–01