Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Headlight Cleaner Motor and Relay Circuit

DESCRIPTION

The headlight cleaner motor and pump assembly is controlled by the headlight ECU sub-assembly RH. When the headlight ECU sub-assembly RH receives the washer switch operation signal 5 times with the low beam headlights on, it operates the H-LP CLN relay once.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses of circuits related to this system before performing the following procedure.

PROCEDURE

1.	PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / (desired system) / Active Test.

(e) Perform the Active Test according to the display on the Techstream.

Body Electrical > AFS > Active Test

Tester Display	Measurement Item	Control Range	Diagnostic Note
Headlight Cleaner	Function to operate the headlight cleaner motor	OFF/ON	*

Body Electrical > HL AutoLeveling > Active Test

Tester Display	Measurement Item	Control Range	Diagnostic Note
Headlight Cleaner	Function to operate the headlight cleaner motor	OFF/ON	*

Body Electrical > AFS > Active Test

Tester Display
Headlight Cleaner

Body Electrical > HL AutoLeveling > Active Test

Tester Display
Headlight Cleaner

OK:

Headlight cleaner motor and pump assembly is normal.

NG

GO TO STEP 4

OK

2.	READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / (desired system) / Data List.

(e) Read the Data List according to the display on the Techstream.

Body Electrical > AFS > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Front Window Washer Switch	Washer switch ON position signal	ON or OFF	ON: Washer switch in ON position OFF: Washer switch not in ON position	*

Body Electrical > HL AutoLeveling > Data List

Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
Front Window Washer Switch	Washer switch ON position signal	ON or OFF	ON: Washer switch in ON position OFF: Washer switch not in ON position	*

Body Electrical > AFS > Data List

Tester Display
Front Window Washer Switch

Body Electrical > HL AutoLeveling > Data List

Tester Display
Front Window Washer Switch

OK:

The Techstream display changes correctly in response to the front washer switch operation.

OK

REPLACE HEADLIGHT ECU SUB-ASSEMBLY RH

NG

3.	CHECK HARNESS AND CONNECTOR (HEADLIGHT ECU SUB-ASSEMBLY - WINDSHIELD WIPER SWITCH ASSEMBLY)

(a) Disconnect the A50 headlight ECU sub-assembly RH connector.

(b) Disconnect the J33 windshield wiper switch assembly connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
A50-18 (FRWA) - J33-7 (WF)	Always	Below 1 Ω
A50-18 (FRWA) or J33-7 (WF) - Body ground	Always	10 kΩ or higher

OK

REPLACE HEADLIGHT ECU SUB-ASSEMBLY RH

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	INSPECT H-LP CLN RELAY

(a) Remove the H-LP CLN relay.

(b) Inspect the H-LP CLN relay.

Click here

NG

REPLACE H-LP CLN RELAY

OK

5.	CHECK HARNESS AND CONNECTOR (H-LP CLN RELAY - POWER SOURCE)

(a) Measure the voltage according to the value(s) in the table below. Standard Voltage: Tester Connection Condition Specified Condition 1 - Body ground Engine switch off Below 1 V Engine switch on (IG) 11 to 14 V

*a Front view of wire harness connector (to H-LP CLN relay)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

6.	CHECK HARNESS AND CONNECTOR (HEADLIGHT CLEANER MOTOR AND PUMP ASSEMBLY CIRCUIT)

(a) Remove the headlight cleaner control relay.

*a Front view of wire harness connector (to Headlight Cleaner Control Relay)

(b) Using a service wire, connect terminal 3 and body ground.

NOTICE:

Do not forcibly insert the service wire into the terminals of the connector when connecting a service wire.

(c) Check the headlight cleaner motor and pump assembly operate.

OK:

Headlight cleaner motor and pump assembly operate.

NG

GO TO STEP 9

OK

7.	CHECK HARNESS AND CONNECTOR (H-LP CLN RELAY - BODY GROUND)

(a) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
5 - Body ground	Always	Below 1 Ω

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

8.	CHECK HARNESS AND CONNECTOR (H-LP CLN RELAY - HEADLIGHT ECU SUB-ASSEMBLY RH)

(a) Disconnect the A50 headlight ECU sub-assembly RH connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
2 - A50-7 (HLC)	Always	Below 1 Ω
2 or A50-7 (HLC) - Body ground	Always	10 kΩ or higher

OK

REPLACE HEADLIGHT ECU SUB-ASSEMBLY RH

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

9.	CHECK HARNESS AND CONNECTOR (HEADLIGHT CLEANER MOTOR AND PUMP ASSEMBLY - POWER SOURCE)

(a) Disconnect the A27 headlight cleaner motor and pump assembly connector.

*a Front view of wire harness connector (to Headlight Cleaner Motor and Pump Assembly)

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection	Condition	Specified Condition
A27-2 - Body ground	Always	11 to 14 V

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

10.	INSPECT HEADLIGHT CLEANER MOTOR AND PUMP ASSEMBLY

(a) Inspect the headlight cleaner motor and pump assembly.

Click here

NG

REPLACE HEADLIGHT CLEANER MOTOR AND PUMP ASSEMBLY

OK

11.	CHECK HARNESS AND CONNECTOR (HEADLIGHT CLEANER MOTOR AND PUMP ASSEMBLY - H-LP CLN RELAY)

(a) Disconnect the A27 headlight cleaner motor and pump assembly connector.

(b) Remove the H-LP CLN relay.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
A27-1 - 3	Always	Below 1 Ω
A27-1 or 3 - Body ground	Always	10 kΩ or higher

OK

USE SIMULATION METHOD TO CHECK

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR