Headlight Relay Circuit

DESCRIPTION

The body ECU controls the headlight relays. The headlight relays 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 USING INTELLIGENT TESTER

1. Connect the intelligent tester to DLC3.

2. Turn the ignition switch to ON position and press 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
   Headlight Relay	Turn Headlight 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 (H-LP R RELAY, H-LP L RELAY)

1. Preparation

   1. Connect the connector.

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

   3. Set the vehicle to the following condition.

      1. Ignition switch ON.
         
      2. Headlight dimmer switch LO.
         

2. Check voltage

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

      Voltage:

      Result	Proceed to
      0 V or Approx. 12 V	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 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 (HEAD LIGHT RELAY)

1. Turn the ignition switch to OFF position.

2. Remove the J/B No.2.

3. Inspect the H-LP R.
   

   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
      LPR (2A-3) - Battery negative terminal	Below 1 V

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

      Symbols (terminals No.)	Connection
      HRLY (2H-8)	Negative

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

      Voltage:

      Tester Connection	Specified Condition
      LPR (2A-3) - Battery negative terminal	10 to 14 V

4. Inspect the H-LP L.

   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
      LPL (2A-2) - Battery negative terminal	Below 1 V

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

      Symbols (terminals No.)	Connection
      HRLY (2H-8)	Negative

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

      Voltage:

      Tester Connection	Specified Condition
      LPL (2A-2) - Battery negative terminal	10 to 14 V

NG	REPLACE JUNCTION BLOCK NO. 2

OK

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

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

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

   Resistance:

   Tester connection	Condition	Specified value
   2H-8 (HRLY) - 1D-3	Always	Below 1 Ω
   2H-8 (HRLY) - 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 bulbs.

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

   Resistance:

   Tester connection	Condition	Specified value
   2A-2 (LPL) - H5-2 (Headlight LH)	Always	Below 1 Ω
   2A-3 (LPR) - H8-2 (Headlight RH)	Always	Below 1 Ω
   2A-2 (LPL) - Body ground	Always	10 kΩ or higher
   2A-3 (LPR) - 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
   H5-1 (Headlight LH) - Body ground	Always	Below 1 Ω
   H8-1 (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 HARNESS AND CONNECTOR (SHORT CIRCUIT DRIVEN SIDE BY RELAY)

1. Preparation

   1. For easier disconnection, remove the J/B No.2 and then take apart the connectors.

   2. Disconnect only the connector "2A".

2. 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 JUNCTION BLOCK NO. 2

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