Headlight (HI-BEAM) Circuit

DESCRIPTION

The body ECU receives headlight HI switch information from the combination switch, and controls the DIM relay. The DIM relay installed in the power distributor.
System diagram of the power distributor (Click here).
System description of the power distributor (Click here).

WIRING DIAGRAM

INSPECTION PROCEDURE

1. PERFORM ACTIVE TEST BY INTELLIGENT TESTER

1. Connect the intelligent tester to DLC3.

2. Turn the ignition switch ON and push the intelligent tester main switch ON.

3. Select the item below in the ACTIVE TEST and then check that the relay operates.

   BODY NO.1 

   Item	Test Details	Diagnostic Note
   Dimmer Signal	Turn Dimmer relay ON/OFF	-

NG	Go to step 2

OK
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

1. Disconnect the connector from the J/B No.2 (power distributor).

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

   Voltage:

   Tester connection	Condition	Specified value
   2I-1 (+B) - Body ground	Always	10 to 14 V

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3. CHECK MODE MONITOR TERMINAL (DIM RELAY)

1. Preparation

   1. Connect the connector.

   2. Remove the cover of the fusible link block assembly.

   3. Set the vehicle to the following conditions:

      1. Ignition switch ON
         
      2. Headlight dimmer switch HI (FLASH)
         

2. Check voltage

   1. Measure the voltage between the Mode Monitor Terminal and body ground.

      Voltage:

      Result	Proceed to
      0 V or Approx. 12V	A
      Approx. 6.2 V	B
      Approx. 2.0 V	C

B	Go to step 5
C	Go to step 9

A

4. CHECK HARNESS AND CONNECTOR (J/B NO.2 - MODE MONITOR TERMINAL)

1. Disconnect the 2G connector from the J/B No.2.

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

Resistance:

Tester connection	Condition	Specified value
2G-5 - Mode monitor terminal	Always	Below 1 Ω
2G-5 - Body ground	Always	10 kΩ or higher

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

5. INSPECT JUNCTION BLOCK NO.2 (DIM RELAY)

1. Turn the ignition switch to OFF position.

2. Remove the J/B No.2.

3. Inspect the DIM relay.
   

   1. Connect the positive battery lead to terminal +B of the J/B No.2 and the negative lead to terminal SGND, PGND.

      Symbols (terminals No.)	Connection
      +B (2I-1) - SGND (2H-13), PGND (2F-1)	Positive - Negative

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

      Voltage:

      Tester Connection	Specified Condition
      DRL2 (2I-2) - Battery negative terminal	Below 1 V

   3. Connect the battery negative lead to terminal DRL of the J/B No.2.

      Symbols (terminals No.)	Connection
      DRL (2H-7)	Negative

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

      Voltage:

      Tester Connection	Specified Condition
      DRL2 (2I-2) - Battery negative terminal	10 to 14 V

NG	REPLACE J/B NO.2

OK

6. CHECK HARNESS AND CONNECTOR (J/B NO.2 - INSTRUMENT PANEL J/B)

1. Disconnect the connectors from the instrument panel J/B.
   

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

   Resistance:

   Tester connection	Condition	Specified value
   2H-7 (DRL) - 1D-9	Always	Below 1 Ω
   2H-7 (DRL) - Body ground	Always	10 kΩ or higher

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

7. CHECK HARNESS AND CONNECTOR (J/B NO.2 - BULB)

1. Disconnect the connectors from the J/B No.2 (power distributor) and headlight bulb.

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

   Resistance:

   Tester connection	Condition	Specified value
   2I-2 (DRL2) - H6-2 (Headlight LH)	Always	Below 1 Ω
   2I-2 (DRL2) - H9-2 (Headlight RH)	Always	Below 1 Ω
   2I-2 (DRL2) - Body ground	Always	10 kΩ or higher

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

8. CHECK HARNESS AND CONNECTOR (BULB - BODY GROUND)

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

   Resistance:

   Tester connection	Condition	Specified value
   H6-1 (Headlight LH) - Body ground	Always	Below 1 Ω
   H9-1 (Headlight RH) - Body ground	Always	Below 1 Ω

NG	REPAIR OR REPLACE HARNESS OR CONNECTOR

OK
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

9. CHECK MODE MONITOR TERMINAL (SHORT CIRCUIT DRIVEN SIDE BY RELAY)

1. Disconnect the 2I connector from the J/B No.2.

2. Connect the battery positive lead to terminal 2I-1 on the J/B side and negative lead to the body ground.

3. Check voltage

   1. Measure the voltage between the Mode Monitor Terminal and body ground.

      Voltage:

      Result	Proceed to
      Approx. 6.2 V	A
      Approx. 2.0 V	B

B	REPLACE J/B NO.2

A
REPAIR OR REPLACE HARNESS OR CONNECTOR (SHORT CIRCUIT BETWEEN HEADLIGHT HI BEAM AND J/B NO.2)