Headlight Relay Circuit [07/2014 - ]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / Main Body / Active Test.
5. According to the display on the Techstream, perform the Active Test.
   MAIN BODY
   
   

   Tester Display	Test Part	Control Range	Diagnostic Note
   Headlight Relay	Headlight relay	OFF or ON	-
   Head Light Hi	Headlight dimmer relay	OFF or ON	Light control switch is in HEAD position

6. Check the illuminating condition of the low beam and high beam headlights.
   RESULT
   
   

   Result	Proceed to
   Low beam headlights and high beam headlights are normal.	A
   Low beam headlights and high beam headlights do not illuminate.	B
   Low beam headlights do not illuminate (High beam headlights are normal).	C
   High beam headlights do not illuminate (Low beam headlights are normal).	D

B → See step   2 

C → See step   8 

D → See step   9 

A → See step   13 

1. Remove the headlight relay (H-LP/US-DRL relay).
2. Inspect the headlight relay (H-LP/US-DRL relay). Refer to ON-VEHICLE INSPECTION [07/2014 - ] .

NG → REPLACE HEADLIGHT RELAY (H-LP/US-DRL RELAY) 

OK: Go to next step 

1. Remove the headlight dimmer relay (DIM relay).
2. Inspect the headlight dimmer relay (DIM relay). Refer to ON-VEHICLE INSPECTION [07/2014 - ] .

NG → REPLACE HEADLIGHT DIMMER RELAY (DIM RELAY) 

OK: Go to next step 

1. Remove the headlight relay (H-LP/US-DRL relay) from the No. 2 engine room relay block.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Voltage

   Tester Connection	Condition	Specified Condition
   H-LP/US-DRL-1 - Body ground	Always	11 to 14 V
   H-LP/US-DRL-3 - Body ground	Always	11 to 14 V

   TEXT IN ILLUSTRATION
   
   

   *1	No. 2 Engine Room Relay Block
   *2	Headlight Rely (H-LP/US-DRL Relay) Holder

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Remove the headlight relay (H-LP/US-DRL relay) from the No. 2 engine room relay block.
2. Remove the headlight dimmer relay (DIM relay) from the No. 2 engine room relay block.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   H-LP/US-DRL-5 - DIM-2	Always	Below 1 Ω
   H-LP/US-DRL-5 - DIM-3	Always	Below 1 Ω
   H-LP/US-DRL-5 or DIM-2 - Body ground	Always	10 kΩ or higher
   H-LP/US-DRL-5 or DIM-3 - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the 3C instrument panel junction block assembly connector.
2. Remove the headlight relay (H-LP/US-DRL relay) from the No. 2 engine room relay block.
3. Remove the headlight dimmer relay (DIM relay) from the No. 2 engine room relay block.
4. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3C-18 - H-LP/US-DRL-2	Always	Below 1 Ω
   3C-35 - DIM-1	Always	Below 1 Ω
   3C-18 or H-LP/US-DRL-2 - Body ground	Always	10 kΩ or higher
   3C-35 or DIM-1 - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Remove the instrument panel junction block assembly.
2. Remove the main body ECU from the instrument panel junction block assembly.
3. Measure the resistance according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   TEXT IN ILLUSTRATION
   
   

   *a	Component without harness connected (Instrument Panel Junction Block Assembly)

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3C-18 - MB-15 (HRLY)	Always	Below 1 Ω
   3C-35 - MB-22 (DIM)	Always	Below 1 Ω

NG → REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY 

OK → See step   13 

1. Remove the headlight dimmer relay (DIM relay).
2. Inspect the headlight dimmer relay (DIM relay). Refer to ON-VEHICLE INSPECTION [07/2014 - ] .

NG → REPLACE HEADLIGHT DIMMER RELAY (DIM RELAY) 

OK → See step   13 

1. Remove the headlight dimmer relay (DIM relay).
2. Inspect the headlight dimmer relay (DIM relay). Refer to ON-VEHICLE INSPECTION [07/2014 - ] .

NG → REPLACE HEADLIGHT DIMMER RELAY (DIM RELAY) 

OK: Go to next step 

1. Remove the headlight relay (H-LP/US-DRL relay) from the No. 2 engine room relay block.
2. Remove the headlight dimmer relay (DIM relay) from the No. 2 engine room relay block.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   H-LP/US-DRL-5 - DIM-2	Always	Below 1 Ω
   H-LP/US-DRL-5 or DIM-2 - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Remove the headlight dimmer relay (DIM relay) from the No. 2 engine room relay block.
2. Disconnect the 3C instrument panel junction block assembly connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   DIM-1 - 3C-35	Always	Below 1 Ω
   DIM-1 or 3C-35 - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Remove the instrument panel junction block assembly.
2. Remove the main body ECU from the instrument panel junction block assembly.
3. Measure the resistance according to the value(s) in the table below.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   TEXT IN ILLUSTRATION
   
   

   *a	Component without harness connected (Instrument Panel Junction Block Assembly)

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   3C-35 - MB-22 (DIM)	Always	Below 1 Ω

NG → REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY 

OK → See step   13