Why is the Battery in My 2003 Chrysler PT Cruiser Continually Going Dead?

Q: I have a 2003 Chrysler PT Cruiser with a 2.4L engine. The battery will not hold a charge for more than 24 hours.

The battery has been replaced twice, along with the alternator and battery cables. What could be causing the battery to keep going dead?

– Maggie Zimmerman from Brooklyn, Michigan

A: Hi, Maggie. It sounds like your PT Cruiser has a parasitic drain on the battery. That means that something is staying turned on (and draining current from the battery) when the ignition is turned off. The source of the drain could be anything from a trunk light bulb staying on to an onboard computer remaining awake.

Devices added on by vehicle owners, such as phone chargers and insurance tracking units, often end up being the source of the parasitic drain. So, if you have any add-on devices installed in the car, start by unplugging those first (if possible). 

If that doesn’t solve the problem, you’ll need to find a mechanic who can track down the source of the drain by performing a parasitic drain test. The procedure involves placing an ammeter in series with (or an amp clamp around) the negative battery cable. 

When performing the test, the ignition should be in the “off” position with the key removed. All of the car’s doors must be closed and any underhood lights and hood switches must be disabled. The onboard computers must also be given enough time to “go to sleep” before performing the test. 

Generally, a drain of more than 50 milliamps is considered excessive. On your particular car, however, the specification is no more than 35 milliamps.

Once a drain is confirmed, most mechanics start pulling the car’s fuses one by one to determine which circuit the drain is coming from. Then they can start unplugging one device at a time within that circuit to pinpoint the drain. 

Good luck! 

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