Lancer L4-2.4L SOHC (2005)
Fog Light Circuit Part 2
CIRCUIT OPERATION
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The ETACS-ECU sends a fog light illumination request signal ("LIGHT ON" signal) to the front-ECU when the fog light switch is turned on while
the headlights are on.
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Then the front-ECU switches on its relay to illuminate the fog lights.
TECHNICAL DESCRIPTION (COMMENT)
If the headlights illuminate normally, the fog light relay, the fog light switch, the front-ECU or the ETACS-ECU may be defective.
TROUBLESHOOTING HINTS
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Trouble in input signal system
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The fog light relay may be defective.
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The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector.
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The front-ECU may be defective.
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The ETACS-ECU may be defective.
DIAGNOSIS
Required Special Tools:
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MB991223: Harness Set
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MB991958: Scan Tool (MUT-III Sub Assembly)
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MB991824: Vehicle Communication Interface (V.C.I.)
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MB991827: MUT-III USB Cable
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MB991911: MUT-III Main Harness B
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MB991813: SWS Monitor Kit
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MB991806: SWS Monitor Cartridge
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MB991812: SWS Monitor Harness (For Column-ECU)
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MB991922: Probe Harness
STEP 1. Verify the headlight operation.
Q: Do the headlights illuminate normally?
The lights illuminate normally at both high and low beams. : Go to Step 2.
Headlights do not Illuminate at low beam : Refer to Inspection Procedure I-2" Headlights (low-beam) do not illuminate normally."
Headlights do not Illuminate at high beam : Refer to Inspection Procedure I-3"Headlights (high-beam) do not illuminate normally."
STEP 2. Check the input signal by using "FUNCTION DIAG." menu of the SWS monitor.
