Headlight Relay Circuit: Procedure

1. Select the ACTIVE TEST, use the Techstream to generate a control command, and then check that the headlight assembly (low) illuminates.
   BODY (MULTIPLEX NETWORK BODY ECU)
   
   

   Item	Test Details	Diagnostic Note
   Headlight Relay	Headlight relay ON / OFF	-

   OK

   Headlight assembly (low) illuminates.

OK → PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE 

NG: Go to next step 

1. Remove the H-LP L LWR fuse from the engine room No. 2 relay block.
2. Remove the H-LP R LWR fuse from the engine room No. 2 relay block.
3. Measure the resistance of the fuses.

   Standard resistance

   Below 1 Ω

NG → REPLACE FUSE 

OK: Go to next step 

1. Remove the HEAD LP relay from the engine room No. 1 relay block.
   Fig 1: Inspecting Head LP Relay

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance of the HEAD LP relay.

   Standard resistance

   Tester Connection	Specified Condition
   3 - 5	10 kΩ or higher
   3 - 5	Below 1 Ω (When battery voltage is applied to terminals 1 and 2)

NG → REPLACE HEAD LP RELAY 

OK: Go to next step 

1. Disconnect the DL junction block connector.
   Fig 2: Checking Wire Harness (Cowl Side Junction Block RH - Battery)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the voltage of the wire harness side connector.

   Standard voltage

   Tester Connection	Specified Condition
   DL-7 (HRLY) - Body ground	10 to 14 V

NG → REPAIR OR REPLACE HARNESS AND CONNECTOR 

OK: Go to next step 

1. Check the wire harness between the headlight (Low LH) and battery, and the headlight (Low LH) and body ground.
   Fig 3: Checking Wire Harness Between Headlight (Low LH) And Battery, And Headlight (Low LH) And Body Ground

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Disconnect the B11 light connector.
   2. Turn the light control switch to the ON (HEAD) position.
   3. Measure the voltage and resistance of the wire harness side connector.

      Standard voltage

      Tester Connection	Specified Condition
      B11-17 (LO) - Body ground	10 to 14 V

      Standard resistance

      Tester Connection	Specified Condition
      B11-16 (E) - Body ground	Below 1 Ω

2. Check the wire harness between the headlight (Low RH) and battery, and the headlight (Low RH) and body ground.
   Fig 4: Checking Wire Harness Between Headlight (Low RH) And Battery, And Headlight (Low RH) And Body Ground

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Disconnect the B2 light connector.
   2. Turn the light control switch to the ON (HEAD) position.
   3. Measure the voltage and resistance of the wire harness side connector.

      Standard voltage

      Tester Connection	Condition	Specified Condition
      B2-17 (LO) - Body ground	Engine switch on (IG)	10 to 14 V

      Standard resistance

      Tester Connection	Specified Condition
      B2-16 (E) - Body ground	Below 1 Ω

OK → REPLACE HEADLIGHT ASSEMBLY (LOW LH OR LOW RH) 

NG: Go to next step 

1. Check the harness and the connectors between the headlight (Low LH or Low RH) and the HEAD LP relay.
   Fig 5: Checking Wire Harness (Headlight (Low LH Or Low RH) - Head LP Relay)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Disconnect the B11 light connector.
   2. Remove the HEAD LP relay from the engine room No. 1 relay block.
   3. Measure the resistance of the wire harness side connectors.

      Standard resistance (Check for open)

      Headlight Assembly	Tester Connection	Specified Condition
      LH	B11-17 (LO) - HEAD LP relay terminal (5)	Below 1 Ω
      RH	B2-17 (LO) - HEAD LP relay terminal (5)	Below 1 Ω

      Standard resistance (Check for short)

      Headlight Assembly	Tester Connection	Specified Condition
      LH	B11-17 (LO) or HEAD LP relay terminal (5) - Body ground	10 kΩor higher
      RH	B2-17 (LO) or HEAD LP relay terminal (5) - Body ground	10 kΩor higher

NG → REPAIR OR REPLACE HARNESS AND CONNECTOR 

OK → PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE