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2016 MDX Base Battery Draining Overnight

0

Mike T. · rep 0 · May 26, 3:55 AM · 1 replies · solved · Question

Vehicle: 2016 Acura MDX Base

My 2016 Acura MDX Base model has a persistent issue with battery drain. If I don't drive it for more than 12-18 hours, the battery is completely dead. I've had the battery tested at an auto parts store, and they said it's good, and the alternator is also charging fine when the car is running.

This has happened several times now, and it's incredibly frustrating to wake up to a dead car. I've checked to make sure no lights are left on. Could there be something else draining the battery? What should I look for?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 26, 3:55 AM

0

ClearTheCode admin answer:

  1. Parasitic Draw Test: This is the most likely culprit. A parasitic draw means something is consuming power even when the car is off. This requires a multimeter connected in series with the battery's negative terminal. After the car "goes to sleep" (which can take 15-30 minutes after turning off), the draw should be very low (typically under 50mA). If it's higher, you'll need to pull fuses one by one to isolate the circuit responsible.
  2. Common Culprits:
    • Aftermarket accessories (stereo, alarm, dash cam) wired incorrectly.
    • Stuck relays (e.g., fuel pump, main relay).
    • Faulty infotainment system components that don't fully shut down.
    • Door lock actuators or trunk latch sensors.
    • Glove box or vanity mirror lights staying on.
    • A failing body control module (BCM).
  3. Battery Age/Quality: While your battery tested "good," sometimes a battery can pass a simple load test but still struggle to hold a charge due to internal resistance, especially if it's several years old. Consider its age.
  4. Alternator Diode Leak: Less common, but a failing diode in the alternator can allow current to flow back to the alternator when the engine is off, draining the battery.
  5. When to See a Shop: Diagnosing a parasitic draw can be time-consuming and requires patience and a good understanding of electrical systems. If you're not comfortable with multimeter testing and systematically pulling fuses, it's highly recommended to take your MDX to an experienced automotive electrician or an Acura dealership. They have the tools and expertise to quickly pinpoint the source of the draw and resolve it, preventing further inconvenience and potential damage to your battery.
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