Low Beam Headlight Circuit: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / Main Body / Active Test.
5. Check that the relays operate.
   MAIN BODY
   
   

   Tester Display	Test Part	Control Range	Diagnostic Note
   Headlight Relay	Headlight relays	ON/OFF	-

   OK

   Headlight relays operate. (Low beam headlights illuminate.)

NG → See step   2 

OK → See step   6 

1. Disconnect the 1H No. 1 integration relay connector.
2. Measure the voltage and resistance according to the value(s) in the table below.

   Standard Voltage

   Tester Connector	Condition	Specified Condition
   1H-7 (BATT) - Body ground	Power switch off	11 to 14 V

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   1H-3 (GND2) - Body ground	Always	Below 1 Ω

3. Disconnect the 1G No. 1 integration relay connector.
4. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   1G-22 (GND1) - Body ground	Always	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Disconnect the 1G No. 1 integration relay connector.
2. Disconnect the 2C 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
   1G-9 (HL4) - 2C-32	Always	Below 1 Ω
   1G-9 (HL4) - 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. Refer to REMOVAL .
   Fig 1: Measuring Resistance Of Instrument Panel Junction Block Assembly

   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
   2C-32 - MB-15 (HRLY)	Always	Below 1 Ω
   2C-32 - Body ground	Always	10 kΩ or higher

   TEXT IN ILLUSTRATION
   
   

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

NG → See step   7 

OK: Go to next step 

1. Temporarily replace the No. 1 integration relay with a new or normally functioning one. Refer to REMOVAL .
2. Check that the low beam headlights operate normally.

   OK

   Low beam headlights operate normally.

NG → See step   8 

OK → END (NO. 1 INTEGRATION RELAY WAS DEFECTIVE)