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2020 Aviator Reserve Battery Draining Overnight - Parasitic Draw Mystery!

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Jason D. · rep 0 · May 22, 6:07 AM · 1 replies · solved · Question

Vehicle: 2020 Lincoln Aviator Reserve

Hey everyone,

I'm pulling my hair out trying to figure out why the battery in my 2020 Lincoln Aviator Reserve keeps dying overnight. It's been happening for about two weeks now. I'll park it in the evening, and by morning, it's completely dead. I've had to jump it several times.

I've checked the obvious things like making sure all lights are off, doors are fully closed, and nothing is plugged into the USB ports. The battery itself is only about a year old, and it tests fine after a full charge. It seems like something is drawing power even when the car is off.

Has anyone else experienced a similar issue with their Aviator or other Lincoln models? Any common culprits for parasitic draws in these vehicles? I'm hoping to get some ideas before I have to take it to the dealership, as I'd prefer to troubleshoot myself if possible.

Thanks for any insights!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 6:07 AM

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ClearTheCode admin answer:

Battery drain, often referred to as a parasitic draw, is a common and frustrating issue. In your 2020 Lincoln Aviator Reserve, several components could be causing this. Here's a breakdown of potential causes and steps to diagnose:

Common Causes of Parasitic Draw:

  • Faulty Modules: Modern vehicles like your Aviator have numerous electronic control modules (ECMs). A module that fails to 'go to sleep' or is constantly active can draw significant power. Common culprits include the infotainment module, telematics unit, or even a door module.
  • Aftermarket Accessories: Any non-factory installed equipment (remote start, dash cam, sound system) can be a source if wired incorrectly or malfunctioning.
  • Stuck Relays: A relay that remains energized when it shouldn't can keep a circuit active.
  • Short Circuits: A short to ground in a wiring harness can create an unintended path for current flow.
  • Aging Battery: While you mentioned your battery is relatively new, a battery with an internal short can also self-discharge rapidly.

Diagnosis Steps:

  1. Perform a Parasitic Draw Test:
    • Ensure the vehicle has been off for at least 30 minutes (to allow all modules to power down).
    • Disconnect the negative battery terminal.
    • Connect a multimeter in series between the negative battery post and the negative battery cable. Set the multimeter to measure amperage (mA or A).
    • A normal draw is typically under 50 mA. If you see a significantly higher reading (e.g., hundreds of mA or amps), you have a draw.
  2. Isolate the Circuit:
    • Once you confirm a draw, start pulling fuses one by one from the fuse box (both under the hood and inside the cabin) while monitoring the multimeter. When the amperage drops significantly, you've found the circuit responsible.
    • Refer to your owner's manual for the fuse box diagram to identify the components on that circuit.
  3. Check for Diagnostic Trouble Codes (DTCs):
    • Even if the check engine light isn't on, a professional scan tool can often reveal 'pending' or 'history' codes related to modules that are not shutting down correctly. Codes like U0100 (Lost Communication with ECM/PCM) or specific B-codes (Body codes) can point to a faulty module.

When to See a Shop:

If you're uncomfortable performing electrical tests, or if you've identified a circuit but can't pinpoint the exact component (e.g., a module that's part of a complex system), it's best to take your Aviator to a qualified Lincoln dealership or an independent shop specializing in automotive electrical diagnostics. They have advanced scan tools and experience to quickly diagnose and repair complex electrical issues.

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