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2018 Pacifica Battery Draining Overnight - Help!

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Sarah K. · rep 0 · May 22, 5:54 AM · 1 replies · solved · Question

Vehicle: 2018 Chrysler Pacifica Touring L

Hey everyone, I'm pulling my hair out with my 2018 Chrysler Pacifica Touring L. For the past few weeks, if I leave it parked overnight, the battery is completely dead by morning. I've had to jump-start it multiple times, and it's getting really frustrating.

I replaced the battery about six months ago, thinking that was the issue, but the problem persists. The alternator seems to be charging fine when the engine is running, showing around 14.4 volts. I've checked for obvious things like lights left on or doors ajar, but everything seems normal.

Could this be a module staying awake, or maybe a faulty sensor? I'm not getting any warning lights on the dash when it's running, but waking up to a dead van every other day is a nightmare. Any ideas on where to start looking?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 5:54 AM

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ClearTheCode admin answer: A parasitic battery drain in your 2018 Chrysler Pacifica can be tricky to diagnose, but it's a common issue. Here's a systematic approach:

  1. Confirm the Drain: First, ensure the battery is fully charged. Then, with the vehicle off and all doors closed (simulate closed with latches if needed), connect a multimeter in series between the negative battery post and the negative battery cable. A normal draw should be around 20-50 milliamps (0.02-0.05 amps) after all modules have gone to sleep (this can take 15-30 minutes). If you see significantly higher, you have a drain.

  2. Fuse Pull Test: While monitoring the amperage draw with the multimeter, systematically pull one fuse at a time from the fuse boxes (under the hood and inside the cabin). When the amperage drops significantly, you've identified the circuit causing the drain. This narrows down the problem area considerably.

  3. Common Culprits for Pacifica:

    • Radio/Infotainment System: Sometimes the Uconnect system can fail to fully shut down.
    • Body Control Module (BCM): A faulty BCM can keep various systems active.
    • Door Ajar Switches: Even if the dash light isn't on, a faulty switch might prevent modules from sleeping.
    • Aftermarket Accessories: Any non-factory installed electronics (dash cams, remote start, etc.) can be a source.
    • Glove Box/Vanity Mirror Lights: These are often overlooked.

  4. Check for OBD Codes: Although you mentioned no dash lights, a scan tool might reveal 'pending' or 'history' codes related to low voltage or module communication issues, such as P0562 (System Voltage Low) or U0100 (Lost Communication with ECM/PCM A), which could point to a module staying awake.

When to See a Shop: If you're uncomfortable performing electrical tests or can't pinpoint the circuit with the fuse pull test, it's best to take your Pacifica to a qualified technician. Diagnosing parasitic drains requires patience and a good understanding of automotive electrical systems. A professional can use advanced diagnostic tools to identify the exact module or component causing the drain, potentially saving you time and further frustration.

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