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2021 Colorado Battery Dead Overnight - Suspect Parasitic Draw

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Emily N. · rep 0 · May 22, 2:36 AM · 1 replies · solved · Question

Vehicle: 2021 Chevrolet Colorado Z71

My 2021 Chevrolet Colorado Z71 keeps dying overnight, and I'm at my wit's end. I've already replaced the battery, and it tests perfectly fine, but if I leave it parked for more than 12-16 hours, it's completely dead. I've checked for lights left on, the glove box, under the hood, everything seems off.

I don't have any aftermarket accessories installed, just the factory setup. Could I have a parasitic draw somewhere that's slowly killing my battery? What's the best way to track something like this down?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 2:36 AM

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ClearTheCode admin answer:

It definitely sounds like your 2021 Chevrolet Colorado Z71 is suffering from a parasitic draw. This is when an electrical component continues to draw power from the battery even when the vehicle is turned off, eventually draining it. Tracking down a parasitic draw can be tricky, but here's a systematic approach:

  1. Confirm the Draw:

    • Connect a multimeter in series between the negative battery post and the negative battery cable. Set the multimeter to measure amperage (Amps).
    • With the vehicle off and all doors closed (simulate 'sleep' mode by waiting 15-30 minutes after closing doors), the draw should ideally be below 50 milliamps (0.05 Amps). Anything significantly higher indicates a draw.

  2. Isolate the Circuit:

    • Once you've confirmed a draw, start pulling fuses one by one from the fuse box (both under the hood and inside the cabin) while watching the multimeter.
    • When the amperage drops significantly after pulling a specific fuse, you've identified the circuit where the draw is occurring. This narrows down your search considerably.

  3. Common Culprits:

    • Radio/Infotainment System: A module that isn't properly shutting down.
    • Body Control Module (BCM): Can sometimes stay 'awake' due to a fault.
    • Glove Box/Trunk Lights: A switch that isn't fully engaging, leaving a light on.
    • Power Seats/Windows: Faulty switches or modules.
    • OnStar/Telematics System: Can sometimes have issues that keep them active.

When to See a Shop: If you're uncomfortable using a multimeter or if you've identified the circuit but can't pinpoint the exact component (e.g., the 'Radio' fuse covers multiple components), it's best to take your Colorado to a professional mechanic. They have advanced diagnostic tools and experience with these types of electrical issues, which can save you a lot of time and frustration.

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