Lexus ES300 (1997 year). Service manual - part 305

S04602

No.1 ECT Switch

CO037–05

P01924

Ohmmeter

S04601

No.2 ECT
Switch

P06722

Ohmmeter

CO–32

–

COOLING

ENGINE COOLANT TEMPERATURE (ECT) SWITCH

949

1997 LEXUS ES300   (RM511U)

ENGINE COOLANT
TEMPERATURE (ECT) SWITCH

INSPECTION

1.

INSPECT NO.1 ECT SWITCH

(a)

Drain engine coolant.

(b)

Remove the ECT switch.

(c)

Using an ohmmeter, check that there is no continuity be-
tween the switch terminals when the coolant temperature
is above 98

°

C (208

°

F).

If there is continuity, replace the switch.
(d)

Using an ohmmeter, check that there is continuity be-
tween the switch terminals when the coolant temperature
is below 88

°

C (190

°

F).

If there is no continuity, replace the switch.
(e)

Install the ECT switch.

(f)

Fill with engine coolant.

2.

INSPECT NO.2 ECT SWITCH

(a)

Drain engine coolant.

(b)

Remove the ECT switch.

(c)

Using an ohmmeter, check that there is continuity be-
tween the switch terminals when the coolant temperature
is above 94

°

C (201

°

F).

(d)

Using an ohmmeter, check that there is no continuity be-
tween the switch terminals when the coolant temperature
is below 83

°

C (181

°

F).

If continuity is not as specified, replace the switch.
(e)

Install the ECT switch.

(f)

Fill with engine coolant.

S05391

Engine
Main Relay

CO038–01

S04944

Ohmmeter

Continuity

Ohmmeter

Ohmmeter

No
Continuity

Continuity

2

1

5

4

3

S04945

Ohmmeter

Ohmmeter

No
Continuity

Continuity

2

1

5

4

3

Battery

–

COOLING

ENGINE MAIN RELAY

CO–33

950

1997 LEXUS ES300   (RM511U)

ENGINE MAIN RELAY

INSPECTION

1.

REMOVE ENGINE MAIN RELAY (Marking: ENGINE
MAIN)

2.

INSPECT RELAY CONTINUITY

(a)

Using an ohmmeter, check that there is continuity be-
tween terminals 3 and 5.

If there is no continuity, replace the relay.
(b)

Check that there is continuity between terminals 2 and 4.

If there is no continuity, replace the relay.
(c)

Check that there is no continuity between terminals 1 and
2.

If there is continuity, replace the relay.

3.

INSPECT RELAY OPERATION

(a)

Apply battery voltage across terminals 3 and 5.

(b)

Using an ohmmeter, check that there is no continuity be-
tween terminals 2 and 4.

If there is continuity, replace the relay.
(c)

Check that there is continuity between terminals 1 and 2.

If there is no continuity, replace the relay.
4.

REINSTALL ENGINE MAIN RELAY

S05390

No.1 Cooling
Fan Relay

CO039–01

S04941

Ohmmeter

Continuity

Ohmmeter

Continuity

4

1

3

2

S04940

No Continuity

Ohmmeter

4

1

3

2

Battery

S04943

Ohmmeter

Continuity

Ohmmeter

Continuity

30

85

86

87a

S04942

Ohmmeter No

Continuity

30

85

86

87a

Battery

CO–34

–

COOLING

COOLING FAN RELAY

951

1997 LEXUS ES300   (RM511U)

COOLING FAN RELAY

INSPECTION

1.

INSPECT NO.1 COOLING FAN RELAY

(a)

Remove the No.1 cooling fan relay. (Marking: FAN NO.1)

(b)

Inspect the No.1 cooling fan relay continuity. (DENSO)
(1)

Using an ohmmeter, check that there is continuity
between terminals 1 and 2.

If there is no continuity, replace the relay.

(2)

Check that there is continuity between terminals 3
and 4.

If there is no continuity, replace the relay.

(c)

Inspect the No.1 cooling fan relay operation. (DENSO)
(1)

Apply battery voltage across terminals 1 and 2.

(2)

Using an ohmmeter, check that there is no continu-
ity between terminals 3 and 4.

If there is continuity, replace the relay.

(d)

Inspect the No.1 cooling fan relay continuity. (BOSCH)
(1)

Using an ohmmeter, check that there is continuity
between terminals 85 and 86.

(2)

If there is no continuity, replace the relay.

(3)

Check that there is continuity between terminals 30
and 87a.

If there is no continuity, replace the relay.

(e)

Inspect the No.1 cooling fan relay operation. (BOSCH)
(1)

Apply battery voltage across terminals 85 and 86.

(2)

Using an ohmmeter, check that there is no continu-
ity between terminals 30 and 87a.

If there is continuity, replace the relay.
(f)

Install the No.1 cooling fan relay.

S05387

No.2 Cooling
Fan Relay

S04948

Ohmmeter

Continuity

Ohmmeter

No Continuity

Continuity

4

1

3

2

Ohmmeter

5

S04949

Ohmmeter

No Continuity

Continuity

4

1

3

2

Ohmmeter

5

Battery

S05388

No.3 Cooling
Fan Relay

S04947

No Continuity

Continuity

1

2

Ohmmeter

5

Ohmmeter

3

–

COOLING

COOLING FAN RELAY

CO–35

952

1997 LEXUS ES300   (RM511U)

2.

INSPECT NO.2 COOLING FAN RELAY

(a)

Remove the No.2 cooling fan relay. (Marking: FAN NO.2)

(b)

Inspect the No.2 cooling fan relay continuity.
(1)

Using an ohmmeter, check that there is continuity
between terminals 1 and 2.

If there is no continuity, replace the relay.

(2)

Check that there is continuity between terminals 3
and 4.

If there is no continuity, replace the relay.

(3)

Check that there is no continuity between terminals
3 and 5.

If there is continuity, replace the relay.
(c)

Inspect the No.2 cooling fan relay operation.
(1)

Apply battery voltage across terminals 1 and 2.

(2)

Using an ohmmeter, check that there is no continu-
ity between terminals 3 and 4.

If there is continuity, replace the relay.

(3)

Using an ohmmeter, check that there is continuity
between terminals 3 and 5.

If there is no continuity, replace the relay.
(d)

Install the No.2 cooling fan relay.

3.

INSPECT NO.3 COOLING FAN RELAY

(a)

Remove the No.3 cooling fan relay. (Marking: FAN NO.3)

(b)

Inspect the No.3 cooling fan relay continuity.
(1)

Using an ohmmeter, check that there is continuity
between terminals 1 and 2.

If there is no continuity, replace the relay.

(2)

Check that there is no continuity between terminals
3 and 5.

If there is  continuity, replace the relay.