LIGHTING SYSTEM Rear Fog Light Circuit

DESCRIPTION

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


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


Tech Tips


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

  • If the vehicle has automatic light control or daytime running light control, the exterior lights (headlights, taillights, front fog lights* and rear fog light) are controlled by the main body ECU.

  • If the vehicle does not have automatic light control or daytime running light control, the exterior lights (headlights, taillights, front fog lights* and rear fog light) are not controlled by the main body ECU. Perform troubleshooting according to the Problem Symptoms Table Click here.

  • Before performing troubleshooting of rear fog light control, check that the low beam headlights and front fog lights* operate normally.


  • *: w/ Front Fog Light

WIRING DIAGRAM

A01IT3IE01

INSPECTION PROCEDURE

Note

Inspect the fuses and bulbs for circuits related to this system before performing the following inspection procedure.

PROCEDURE


  1. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (REAR FOG LIGHT RELAY)


    1. Using the intelligent tester, perform the Active Test Click here.

      Main Body
      Tester Display Test Part Control Range Diagnostic Note
      Rear Fog Light Relay Rear fog light relay ON/OFF -
      OK
      Rear fog light relay operates (rear fog light comes on).

    NG

    READ VALUE USING INTELLIGENT TESTER (REAR FOG LIGHT SWITCH) Click here

    OK

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

  2. READ VALUE USING INTELLIGENT TESTER (REAR FOG LIGHT SWITCH)


    1. Using the intelligent tester, read the Data List Click here.

      Main Body
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Rear Fog Light SW Rear fog light switch signal / ON or OFF

      ON: Rear fog light switch on

      OFF: Rear fog light switch off

      		 -
      OK
      The display is as specified in the normal condition column.

    NG

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

    OK

  3. INSPECT REAR FOG LIGHT RELAY (RR FOG)

    A01IQG5E01

    1. Remove the rear fog light relay from the No. 3 relay block.

    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
      3 - 5 Battery voltage applied between terminals 1 and 2 Below 1 Ω

    NG

    REPLACE REAR FOG LIGHT RELAY

    OK

  4. CHECK HARNESS AND CONNECTOR (BATTERY - REAR FOG LIGHT RELAY [RR FOG])

    A01IOK0E03
    Text in Illustration
    *1 No. 3 Relay Block
    *2 Rear Fog Light Relay (RR FOG)

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      Rear fog light relay terminal 5 - Body ground Always 11 to 14 V
      Rear fog light relay terminal 2 - Body ground Light control switch off → tail Below 1 V → 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK HARNESS AND CONNECTOR (REAR FOG LIGHT RELAY [RR FOG] - MAIN BODY ECU)

    A01INW1E03

    1. Disconnect the H80 main body ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      Rear fog light relay terminal 1 - H80-11 (RFGO) Always Below 1 Ω
      H80-11 (RFGO) - Body ground Always 10 kΩ or higher
      Text in Illustration
      *1

      Front view of wire harness connector

      (to Main Body ECU)

      		 *2 No. 3 Relay Block
      *3 Rear Fog Light Relay (RR FOG) - -

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

    A01ISAJE12
    Text in Illustration
    *1

    Component with harness connected

    (Main Body ECU)

    1. Reconnect the H80 main body ECU connector.

    2. Install the rear fog light relay to the No. 3 relay block.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      H80-11 (RFGO) - Body ground Light control switch in head and rear fog light switch off 11 to 14 V
      Light control switch in head and rear fog light switch on Below 1 V

    NG

    REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

    OK

    REPAIR OR REPLACE HARNESS OR CONNECTOR (REAR FOG LIGHT RELAY [RR FOG] - REAR COMBINATION LIGHT ASSEMBLY [REAR FOG LIGHT])