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Old 08-15-2011, 08:33 PM   #1
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Electrical Issues

My car has a draw on the battery of about 1600 mA after I turn off the ignition and remove the key. It should be much lower (like 30-50mA). Basically it will hold a charge overnight, but the battery is dead after a couple of days without use.

The battery is new, and a meter confirmed that the alternator is working normally.

Something isn't right, like a light staying on or a sensor not working.

Has anyone had a problem like this? Any likely culprits? Suggestions? Thanks.


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Old 08-15-2011, 09:01 PM   #2
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Remove the fuse....

...one at a time to isolate which circuit is "closed" and drawing too much current.
BTW, I don't know if the current you reported is "normal" or not. My suggestion is based on the assumption that you are drawing too much current when the car is "off."

Good luck.

P.S. Start with the easy ones: the lights under/inside the trunks.

Last edited by mikehkang; 08-15-2011 at 09:07 PM.
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Old 08-15-2011, 09:12 PM   #3
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Be sure that you have the DMM connected between the pos (+) battery terminal and the battery cable.

Then, as mentioned, pull fuses one by one to see which circuit is the culprit (because pulling the fuse stops the current draw).

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Old 08-16-2011, 09:51 AM   #4
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My car only measures 21 milliamps when I thought I had a parasitic drag, so my car was actually OK, thank goodness. I checked mine after being shut down for 2 hours so the trunk light was off even though the front trunk lid was open. I checked mine by hooking up a temporariy battery in the cigarette lighter that's meant to be used during a battery replacement to retain the radio functions, etc. Then I disconnected the negative post on the battery and hooked up my meter to the post on one side and the battery cable on the other. Then I unhooked the temporary battery gizmo from the cigarette lighter socket and read the multi-meter.

You'd expect a genuine draw to be on a system that is functional regardless of key position. Front and rear trunk lights are possibilities and maybe the power seats. I don't know what else is on all the time, even after the 2 hour shutdown timer that kills the power to some stuff.

I guess if you checked by pulling the fuses you'd first have to pull the fuse for the interior lights because they're going to come on when you open the doors and you can't pull the fuses with the doors closed (maybe a midget could do it).
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Old 08-16-2011, 06:39 PM   #5
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Well, now we're on ignition switch number 3...

Hopefully all fixed up.

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Old 08-16-2011, 06:52 PM   #6
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so here is the rest of the story:

I flew home on Friday after traveling all week on business. I put the key in the door and window didn't slide down. I think, hey that's weird. Put the key in the ignition and...nothing. Uggh. Dead battery.

So I make the call to the security folks and ask for a jumpstart. I pull the little thing out of the fuse box so we can attach the jumper cables and open the front trunk so we can access the battery. We attach the cables and BLAM BLAM BLAM BLAM the car alarm goes off. No big deal, I put my key into the ignition and turn the switch -- nothing. Alarm is relentless. Until you deactivate the alarm the switch for the front trunk is not activated.

I also try the key in the door, no luck at all. My car doesn't have a clicker in the key, so that wasn't an option. Turns out there is no way to get to the battery from the parking lot of airport. Worst design ever. Just give me a damn manual lever.

Eventually I give up and call AAA.

It gets better, so the tow truck guy says "where are you", I tell him. He says "I can't get in there, so you'll need to get out past the tolls". I tell him, "dude, my car is dead. that is like a quarter mile away, why do you think I called for a flatbed". He says "I don't know push it or something". I just laughed at him. You can't make this stuff up.

Ultimately the flatbed driver found me, we took the car home. It didn't take :30 seconds to jumpstart the car with the portable battery. Some power to the cigarette lighter allowed me to pop the trunk and the car jumpstart right away.

The culprit was the ignition switch. It allowed the dim amber night light to stay on and killed the battery. I hope I am all good now, but what a frustrating weekend.
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Old 08-17-2011, 05:55 AM   #7
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You know, we pay a good price for our Porsche, but the CEO of Porsche wants to maximize his profits so they cut corners where ever they can. I love my Boxster but key components must be above spec. No cheap stuff.


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