Headlight Relay Circuit: Procedure

1. Using the Techstream, perform the Active Test. Refer to DATA LIST / ACTIVE TEST .
   MAIN BODY
   
   

   Tester Display	Test Part	Control Range	Diagnostic Note
   Headlight Relay	Low beam headlight relay	ON/OFF	-

   OK

   Headlight relay operates (low beam headlights illuminate).

NG → See step   2 

OK → See step   5 

1. Remove the headlight relay from the engine room relay block, junction block.
   Fig 1: Headlight Relay (H-LP LO)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3 - 5	Battery voltage not applied between terminals 1 and 2	10 kΩ or higher
   	Battery voltage applied between terminals 1 and 2	Below 1 Ω

NG → REPLACE HEADLIGHT RELAY 

OK: Go to next step 

1. Measure the voltage according to the value(s) in the table below.
   Fig 2: Identifying Headlight Relay [H-LP LO] Connector Terminals

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   Headlight relay terminal 1 - Body ground	Always	11 to 14 V
   Headlight relay terminal 5 - Body ground

   TEXT IN ILLUSTRATION
   
   

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

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Remove the main body ECU. Refer to REMOVAL .
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   Headlight relay terminal 2 - A-15 (HRLY)	Always	Below 1 Ω
   A-15 (HRLY) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   5