Headlight (Hi-Beam) Circuit

LIGHTING: LIGHTING SYSTEM: Headlight (HI-BEAM) Circuit
- Headlight (HI-BEAM) Circuit

DESCRIPTION

The main body ECU receives dimmer switch HIGH signal and light control switch HEAD signal from the headlight dimmer switch assembly, and turns the high beam headlights on.

HINT
When a short circuit occurs between the power distributor (engine room J/B assembly) and high beam headlight, the power distributor stops the DRL relay operation (Fail-safe function).

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect Techstream to the DLC3.

(b) Turn the ignition switch on (IG).

(c) Turn Techstream on.

(d) Select the following menu items: Body Electrical / Main Body / Active Test.

(e) Check that the relay operates.

Main Body:





OK:

Relay operates. (HI-beam headlights illuminate.)

OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
NG -- Continue to next step.

2. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

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





Standard voltage:





OK -- CHECK HARNESS AND CONNECTOR (SHORT IN RELAY-DRIVEN CIRCUIT)
NG -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (ENGINE ROOM J/B ASSEMBLY - BATTERY AND BODY GROUND)

(a) Disconnect the 1G engine room J/B assembly connector.





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

Standard voltage:





(c) Disconnect the 1E engine room J/B assembly connector.





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

Standard resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

4. INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY

(a) Reconnect the 1G and 1E engine room J/B assembly connectors.

(b) Disconnect the 1D engine room J/B assembly connector.





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

Standard voltage:





NG -- REPLACE ENGINE ROOM JUNCTION BLOCK ASSEMBLY (POWER DISTRIBUTOR)
OK -- Continue to next step.

5. CHECK HARNESS AND CONNECTOR (ENGINE ROOM J/B ASSEMBLY - INSTRUMENT PANEL J/B ASSEMBLY)

(a) Reconnect the 1D engine room J/B assembly connector.

(b) Disconnect the ID instrument panel J/B connector.





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

Standard voltage:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

6. CHECK HARNESS AND CONNECTOR (SHORT IN RELAY-DRIVEN CIRCUIT)

(a) Remove the H-LP (RH) fuse from the engine room J/B assembly.





(b) Turn the light control switch to the HEAD position and turn the dimmer switch to the HIGH position.

(c) Check if the high beam headlight LH illuminates.

(d) Turn the dimmer switch to the LOW position.

(e) Install the H-LP (RH) fuse and remove the H-LP (LH) fuse.

(f) Turn the dimmer switch to the HIGH position.

(g) Check if the high beam headlight RH illuminates.

OK:

Either high beam headlight LH or RH illuminates.

OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (SHORT CIRCUIT BETWEEN FUSE AND BULB)
NG -- Continue to next step.

7. INSPECT ENGINE ROOM JUNCTION BLOCK ASSEMBLY

(a) Remove the H-LP (RH) fuse and H-LP (LH) fuse from the engine room J/B assembly.





(b) Measure the voltage between the loading slot of each fuse and body ground.

Standard voltage:





NG -- REPLACE ENGINE ROOM JUNCTION BLOCK ASSEMBLY (POWER DISTRIBUTOR)

OK -- REPAIR OR REPLACE HARNESS OR CONNECTOR (OPEN CIRCUIT BETWEEN FUSE AND BODY GROUND)