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Battery Drain & Random Warning Lights on 2018 LaCrosse

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Steve N. · rep 0 · May 22, 3:54 AM · 1 replies · solved · Question

Vehicle: 2018 Buick LaCrosse Premium

I have a 2018 Buick LaCrosse Premium, and lately, the battery keeps dying if I don't drive it for a couple of days. It's incredibly frustrating to come out to a dead car. I've already replaced the battery once, thinking that was the issue, but it's still happening.

On top of that, I've noticed some random warning lights flashing on the dash, like ABS or StabiliTrak, even though the car seems to drive fine otherwise. Could this be a parasitic draw, or something more serious going on with the electrical system? Any common culprits for these models?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 3:54 AM

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ClearTheCode admin answer:

Battery drain combined with random warning lights on your 2018 Buick LaCrosse Premium strongly suggests a parasitic draw or a failing electrical component. Here's how to approach it:

  1. Diagnosing Parasitic Draw:
    • Test Procedure: A parasitic draw test involves connecting an ammeter in series with the battery's negative terminal and then systematically pulling fuses to identify which circuit is drawing excessive current when the car is off.
    • Common Culprits: For Buick models, common sources of parasitic draws can include:
      • Infotainment System Modules: Sometimes they don't fully shut down.
      • OnStar Module: Known to cause drains in some GM vehicles.
      • HVAC Blower Motor Resistor: Can sometimes stay partially active.
      • Aftermarket Accessories: Anything wired directly to the battery.
      • Faulty Relays: A relay stuck in the 'on' position.
  2. Battery and Alternator Health:
    • Even with a new battery, ensure it's fully charged and load-tested. A faulty new battery is rare but possible.
    • Have the alternator tested. A weak alternator won't properly charge the battery, leading to repeated drains, though this usually manifests as a 'Battery' warning light while driving.
  3. Random Warning Lights:
    • Low Voltage: Many modern vehicle systems (ABS, StabiliTrak, power steering) are highly sensitive to voltage fluctuations. A consistently low battery or intermittent power supply can trigger these warning lights, even if the underlying system is fine.
    • Faulty Sensors/Modules: Less likely to cause a drain, but a failing ABS module or wheel speed sensor could trigger specific lights.

When to See a Shop: Diagnosing a parasitic draw can be time-consuming and requires specific tools and expertise. If you're not comfortable performing electrical diagnostics, it's best to take your LaCrosse to a qualified automotive electrician or a Buick dealership. They can accurately pinpoint the source of the draw and address the root cause of both the battery drain and the warning lights.

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