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2017 LaCrosse Headlights Flickering and Going Out

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David L. · rep 0 · May 25, 2:46 AM · 1 replies · solved · Question

Vehicle: 2017 Buick LaCrosse Premium

I'm having a serious safety concern with my 2017 Buick LaCrosse Premium. Both headlights, especially the low beams, will flicker randomly while I'm driving, and sometimes they just turn off completely for a few seconds before coming back on. It's incredibly unnerving, especially at night.

I also get a 'Service Headlight System' message on the dash whenever this happens. It seems to be getting worse over time. I haven't hit any major potholes or done anything that would obviously damage them.

Could this be a bad headlight control module, a wiring issue, or perhaps a problem with the bulbs or ballasts themselves (if they're HID)? Any guidance on what to check first would be greatly appreciated.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 2:46 AM

0

ClearTheCode admin answer:

Flickering and intermittent headlight failure on your 2017 Buick LaCrosse Premium, accompanied by a 'Service Headlight System' message, is a critical safety issue that needs immediate attention. This problem often points to issues within the headlight's electrical circuit. Given your model year, your LaCrosse likely uses Xenon High-Intensity Discharge (HID) headlights for low beams.

  1. Check Bulbs and Ballasts (if HID):

    • Cause: HID systems use a ballast to ignite and power the Xenon bulb. A failing ballast or a worn-out HID bulb can cause flickering, dimming, or complete intermittent failure before eventually going out for good.
    • Steps: If one light is acting up more than the other, try swapping the bulbs (if accessible and safe to do so) between sides to see if the problem follows the bulb. If the problem remains on the same side, the ballast is a strong suspect.

  2. Inspect Wiring and Connections:

    • Cause: Loose, corroded, or damaged wiring and connectors leading to the headlights or ballasts can cause intermittent power supply, resulting in flickering or failure.
    • Steps: Visually inspect the wiring harnesses around the headlights for any signs of fraying, corrosion, or looseness. Pay close attention to the connectors at the bulb, ballast, and the main headlight assembly.

  3. Headlight Control Module (HCM) / Body Control Module (BCM):

    • Cause: Modern vehicles often have a dedicated Headlight Control Module or integrate headlight control functions into the Body Control Module (BCM). A fault in this module can send incorrect power signals or misinterpret sensor data, leading to erratic behavior.
    • Steps: A diagnostic scan tool can often pull specific codes related to the HCM or BCM, indicating an internal fault or communication issue. Common codes might include U-codes (network communication) or B-codes (body electrical).

  4. Ground Connections:

    • Cause: Poor ground connections for the headlight circuits can lead to voltage drops and flickering.
    • Steps: Inspect the ground points in the engine bay, usually near the headlights or battery, for corrosion or looseness.

When to See a Shop: Due to the safety implications, it's highly recommended to have your LaCrosse inspected by a certified Buick technician or an automotive electrical specialist as soon as possible. Diagnosing these issues often requires specialized tools to test voltage, current, and module communication. Driving with unreliable headlights is extremely dangerous, especially at night.

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