Lancer L4-2.4L SOHC (2005)
Headlight Relay (High-beam) Circuit
CIRCUIT OPERATION
When the dimmer switch is turned on, the column switch sends a signal to the front-ECU. Then the front-ECU switches the headlights from low-beam to
high beam or vice versa.
TECHNICAL DESCRIPTION (COMMENT)
If the headlights (high beam) do not illuminate normally, the column switch or the front-ECU may be defective.
TROUBLESHOOTING HINTS
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The column switch (turn-signal light and lighting switch) may be defective
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The front-ECU 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
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. Use scan tool MB991958 to select "ECU COMM CHK" on the SWS monitor display.
Check the following ECUs:
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Column-ECU
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Front-ECU
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or
disconnecting scan tool MB991958. Connect the DLC harness before connecting the column-ECU harness. Be sure to connect SWS monitor kit
MB991813 after turning on scan tool MB991958.
