LIGHTING SYSTEM Front Fog Light Circuit

DESCRIPTION

• This circuit is only for vehicles with the daytime running light system or with automatic light control system.

  Tech Tips

  
  

  • For vehicles with the daytime running light system or with automatic light control system, the exterior lights (headlights, taillights, front fog lights and rear fog light) are controlled by the main body ECU.

  • For vehicles without the daytime running light system and without automatic light control system, the exterior lights (headlights, taillights, front fog lights, and rear fog light) are not controlled by the main body ECU, so perform troubleshooting according to the Problem Symptoms Table Click here.

• When all of the following conditions are met, the front fog lights come on.




• Taillights are turned on by the automatic light control or manual light control.

• Front fog light switch is on.

• When any of the following conditions is met, the front fog lights turn off.




• Front fog light switch is off.

• Taillights are off.

  Tech Tips

  
  

  • Before performing troubleshooting of the front fog light control, check that the taillights operate normally.

  • If a front fog light on only one side does not illuminate, inspect the front fog light or wire harness that is related to the front fog light.

  • If both right and left front fog lights do not illuminate, perform the front fog light relay Active Test and read the front fog light switch value in the Data List to determine if the malfunction exists on the switch side or the relay side.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. PERFORM ACTIVE TEST USING INTELLIGENT TESTER

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the ignition switch to ON.

   3. Turn the tester on.

   4. Enter the following menus: Body / Main Body / Active Test.

   5. According to the display on the tester, perform the Active Test.

      Main Body

      Tester Display	Test Part	Control Range	Diagnostic Note
      Front Fog Light Relay	Front fog light relay	ON or OFF	-

      OK
      Front fog light relay operates. (Front fog lights come on.)

   
   

   NG

   READ VALUE USING INTELLIGENT TESTER Click here

   OK

   PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

2. READ VALUE USING INTELLIGENT TESTER

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the ignition switch to ON.

   3. Turn the tester on.

   4. Enter the following menus: Body / Main Body / Data List.

   5. According to the display on the tester, read the Data List.

      Main Body

      Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
      Front Fog Light SW	Front fog light switch signal ON or OFF	ON: Front fog light switch ON OFF: Front fog light switch OFF	-

      OK
      Normal conditions listed above are displayed.

   
   

   NG

   PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

   OK

3. INSPECT FRONT FOG LIGHT RELAY

   
   

   1. 

      Remove the front fog light relay from the No. 4 relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition 3 - 5 Voltage is not applied between terminals 1 and 2 10 kΩ or higher Apply the battery voltage between terminals 1 and 2 Below 1 Ω

   3. Reinstall the front fog light relay.

   
   

   NG

   REPLACE FRONT FOG LIGHT RELAY

   OK

4. CHECK HARNESS AND CONNECTOR (BATTERY - FRONT FOG LIGHT RELAY)

   
   
   1. 

      Text in Illustration

      *1	Component without relay connected (No. 4 Relay Block)
      *2	FR FOG Relay

      Remove the front fog light relay from the No. 4 relay block.

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

      Standard Voltage
      Tester Connection Condition Specified Condition Front fog light relay terminal 5 - Body ground Always 11 to 14 V Front fog light relay terminal 2 - Body ground Light control switch OFF → TAIL Below 1 V → 11 to 14 V

   3. Reinstall the front fog light relay.

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

5. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK - FRONT FOG LIGHT RELAY)

   
   
   1. 

      Text in Illustration

      *1	Front view of wire harness connector (to Instrument Panel Junction Block)
      *2	Component without relay connected (No. 4 Relay Block)
      *3	FR FOG Relay

      Remove the front fog light relay from the No. 4 relay block.

   2. Disconnect the 3C instrument panel junction block connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Front fog light relay terminal 1 - 3C-29 Always Below 1 Ω 3C-29 - Body ground Always 10 kΩ or higher

   4. Reinstall the front fog light relay.

   5. Reconnect the instrument panel junction block connector.

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

6. CHECK HARNESS AND CONNECTOR (FRONT FOG LIGHT - FRONT FOG LIGHT RELAY AND BODY GROUND)

   
   
   1. 

      Text in Illustration

      *1	Front view of wire harness connector (to Front Fog Light)
      *2	Component without relay connected (No. 4 Relay Block)
      *3	LH side
      *4	RH side
      *5	FR FOG Relay

      Remove the front fog light relay from the No. 4 relay block.

   2. Disconnect the A6 or A13 front fog light connector.

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

      Standard Resistance
      LH Side Tester Connection Switch Condition Specified Condition Front fog light relay terminal 3 - A6-2 Always Below 1 Ω Front fog light relay terminal 3 - Body ground Always 10 kΩ or higher A6-1 - Body ground Always Below 1 Ω
      RH Side Tester Connection Switch Condition Specified Condition Front fog light relay terminal 3 - A13-2 Always Below 1 Ω Front fog light relay terminal 3 - Body ground Always 10 kΩ or higher A13-1 - Body ground Always Below 1 Ω

   4. Reinstall the front fog light relay.

   5. Reconnect the front fog light connector.

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

7. REPLACE MAIN BODY ECU

   
   

   1. Temporarily replace the main body ECU with a new or normally functioning one Click here.

   
   

   NEXT

8. PERFORM ACTIVE TEST USING INTELLIGENT TESTER

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the ignition switch to ON.

   3. Turn the tester on.

   4. Enter the following menus: Body / Main Body / Active Test.

   5. According to the display on the tester, perform the Active Test.

      Main Body

      Tester Display	Test Part	Control Range	Diagnostic Note
      Front Fog Light Relay	Front fog light relay	ON or OFF	-

      OK
      Front fog light relay operates. (Front fog lights come on.)

   
   

   NG

   REPLACE INSTRUMENT PANEL JUNCTION BLOCK

   OK

   END (MAIN BODY ECU DEFECTIVE)