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Lexus ES300 (2002 year). Manual - part 45

293

Engine Control Module

E 7(B), E 8(C)

A/CS

ACMG

LCKI

Y–G

P–

W–

THR

A/CI

Y–

IL1

* 2 : w/o VSC

* 1 : w/ VSC

IF5

iode

(A/

)

D 1

L–

–W

Y–

P–L

Y–B

129

109

118

Junction
Connector

J11

IK1

P–

Y–

105

125

126

106

Y–

THWO

14 B

Y–G

(* 1)
(* 2)

(*1)
(*2)

V–W

r T

peedom

(* 1)
(* 2)

Y–

Power

Micro Computer

10A
GAUGE1

From Power Source System (See Page 56)

inat

ion M

ter

C 7

294

Air Conditioning

1. Heater Blower Operation

Manual operation
When the blower speed is set to a certain level using the blower control SW, the A/C control assembly sends the signals to
the blower control to control the blower motor speed.
Auto operation
When the auto SW is turned on, the A/C control assembly sends the signals from various sensors and temperature SW to
the blower control to automatically control the blower motor speed.

2. Air Inlet Control Servo Motor Control

When the FRESH/RECIRC select SW is set to RECIRC, the motor in the air inlet control servo motor starts rotating to move
the damper toward the RECIRC side. Since the damper position is detected by the TERMINAL TPI of the A/C control
assembly, the motor is continuously rotated until the damper reaches its stop position.When the FRESH/RECIRC select SW
is set to FRESH, the motor in the air inlet control servo motor starts rotating to move the damper toward the FRESH side.
Since the damper position is detected by the TERMINAL TPI of the A/C control assembly, the motor is continuously rotated
until the damper reaches its stop position.

3. Air Vent Mode Control Servo Motor Control

When the mode select SW is pushed, the ECU in the A/C control assembly activates the air vent mode control servo motor.
This causes the servo motor to rotate to the position (FACE, BI–LEVEL, FOOT, FOOT/DEF, DEF) selected using the mode
select SW, and moves the damper.

4. Air Mix Control Servo Motor Control

When the temperature control SW on the driver’s side is pressed, the ECU in the A/C control assembly sends a signal to the
air mix control servo motor on the driver’s side. This signal drives the motor to reach the temperature set by the temperature
control SW on the driver’s side, and moves the damper. Passenger’s side is operated as same as the driver’s side.

5. Air Conditioning Operation

The A/C control assembly receives various signals, I.E., the engine RPM from the engine control module, out side air
temperature signal from the A/C ambient temp. sensor, coolant temperature from the engine control module and the lock
signal from the A/C compressor, etc.
When the engine is started and the A/C SW (A/C control assembly) is on, a signal is input to the A/C control assembly.
As a result, the ground circuit in A/C control assembly is closed and current flows from HTR (10A) fuse to TERMINAL 1 of
the MG CLT relay to TERMINAL 2 to TERMINAL 3 of the diode (A/C) to TERMINAL 2 to TERMINAL ACMG of the engine
control module to TERMINAL HP to GROUND, turning the MG CLT relay on, so that the magnetic clutch is on and the A/C
compressor operates.
At the same time, the engine control module. Detects the magnetic clutch is on and the A/C compressor operates.
If the A/C control assembly detects the following conditions, it stops the air conditioning:

∗

Evaporator outlet air is too low.

∗

There is a marked difference between the compressor speed and the engine speed.

∗

The refrigerant pressure is abnormally high or abnormally low.

∗

The engine speed is too low.

∗

Rapid acceleration occurs.

P4 Pressure SW

1–4 : Open with the refrigerant pressure at less than approx. 216 kpa (2.2 kgf/cm

31 psi) or more than

approx. 3138 kpa (32 kgf/cm

455 psi)

A15 (B) A/C Control Assembly

+B–Ground : Always approx. 12 volts

IG–Ground : Approx. 12 volts with ignition SW at ON or ST position

AIF–Ground : Approx. 12 volts with FRESH SW on

AIR–Ground : Approx. 12 volts with RECIRC SW on

GND–Ground : Always continuity

System Outline

Service Hints

295

: Parts Location

Code

See Page

Code

See Page

Code

See Page

A19

A26

A13

A27

A14

A28

A15

A29

J11

A17

A18

T11

: Relay Blocks

Code

See Page

Relay Blocks (Relay Block Location)

Engine Room R/B (Engine Compartment Left)

: Junction Block and Wire Harness Connector

Code

See Page

Junction Block and Wire Harness (Connector Location)

Engine Room Main Wire and Engine Room J/B (Engine Compartment Left)

Engine Wire and Engine Room J/B (Engine Compartment Left)

Engine Room Main Wire and Driver Side J/B (Lower Finish Panel)

Instrument Panel Wire and Driver Side J/B (Lower Finish Panel)

34 (w/ VSC)

35 (w/o VSC)

Instrument Panel Wire and Passenger Side J/B (Instrument Panel Brace RH)

34 (w/ VSC)

Instrument Panel Wire and Passenger Side J/B (Instrument Panel Brace RH)

35 (w/o VSC)

: Connector Joining Wire Harness and Wire Harness

Code

See Page

Joining Wire Harness and Wire Harness (Connector Location)

IA2

Instrument Panel Wire and Floor No.1 Wire (Left Kick Panel)

IF3

IF5

Engine Room Main Wire and Instrument Panel Wire (Right Side of Steering Column Tube)

IF7

( g

)

IG1

Instrument Panel Wire and Engine Room Main Wire (Instrument Panel Brace LH)

IJ1

Instrument Panel Wire and Instrument Panel No.3 Wire (Left Side of A/C Unit)

IK1

Instrument Panel Wire and Instrument Panel Wire (Instrument Panel Reinforcement RH)

IL1

Engine Wire and Instrument Panel Wire (Behind the Glove Box)

IM1

Instrument Panel Wire and Cowl No.2 Wire (Behind the Glove Box)

: Ground Points

Code

See Page

Ground Points Location

Right Fender

Left Fender

Intake Side of Cylinder Block

Instrument Panel Reinforcement LH

Instrument Panel Brace RH

Instrument Panel Reinforcement RH

: Splice Points

Code

See Page

Wire Harness with Splice Points

Code

See Page

Wire Harness with Splice Points

Instrument Panel No.2 Wire

Power Source

FL MAIN
3. 0W

Battery

10A FAN RLY

10A GAUGE1

10A GAUGE2

10A HTR

15A SUN–SHADE

15A WASHER

20A SEAT HTR

B–Y

IG1 Relay

DEF Relay

ACC Relay

TAIL Relay

10A MIR HTR

10A RAD NO. 2

15A CIG

15A POWER POINT

10A TAIL

10A PANEL

25A AMP

20A PWR NO. 2

20A PWR NO. 3

30A PWR NO. 1

B–

B–G

Generator

G 1

5A FUEL OPEN

7. 5A OBD

15A FOG

15A STOP

20A PWR NO. 4

30A PWR SEAT

40A DEF

25A WIPER

10A ECU–IG

5A ECU–ACC

5A AM1

L–R

B–

B–G

25A DOOR NO. 2

A AL

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