SL/R230: Consumer Battery Drain When Trunk Closed
06-23-2019, 01:03 PM
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Consumer Battery Drain When Trunk Closed
Hello Members,
I am hoping for some help to diagnose a parasitic drain issue. First a couple of background details. Mostly this car stays in the garage and is driven a couple of times a month. This is a 2009 SL550 with 49K on it. Last service was an oil change 4 months ago and before that a starter battery replacement 9 months ago.
Reflecting back the problem started 2-3 months ago. I noticed a red "BRAKE" light on the instrument cluster. It went away and I had brakes so didn't think too much about it. I noticed it a few times but it seemed like it went away as fast as it showed up. The car stays unlocked in the garage and one day I opened the door and the windows didn't go down, the dome lights didn't come on and the car wouldn't start with the Keyless Go. I used the key and the car started, rolled the windows down and then back up and drove off. Apparently driving it re-charged the consumer battery and all was well or so I thought. Typically I don't put it on a trickle charger since I drive it just enough to not need one.
The next morning mostly the same symptoms so I thought the battery had a bad cell. Took it out and had it tested and was good. I was a little disappointed since a 200.00 battery was probably going to be my least expensive solution. Over the next couple of weeks I performed various experiments with the multimeter tool, charger and trunk open and closed. I even had the trunk open and simulated it being closed by manually engaging the latch. I have an Innova 3160D code scanner tool and it did not pull up any codes.
The bottom line is that when the trunk is open there is a normal drain on the battery. When the trunk is closed the battery will lose 2-3 volts overnight or in 8 hours or so. I'm hoping someone can help point me in the right direction or provide insight as to what is coming on when the trunk is closed. Not sure of the sticky on the slow close trunk repair will help but that is the next step on my troubleshooting adventure to see if there is a leak that could be making the pump come on-although I am in the garage a lot and have not heard anything come on.
Thanks for reading this. Any help will be appreciated!
Thanks,
Bo
I am hoping for some help to diagnose a parasitic drain issue. First a couple of background details. Mostly this car stays in the garage and is driven a couple of times a month. This is a 2009 SL550 with 49K on it. Last service was an oil change 4 months ago and before that a starter battery replacement 9 months ago.
Reflecting back the problem started 2-3 months ago. I noticed a red "BRAKE" light on the instrument cluster. It went away and I had brakes so didn't think too much about it. I noticed it a few times but it seemed like it went away as fast as it showed up. The car stays unlocked in the garage and one day I opened the door and the windows didn't go down, the dome lights didn't come on and the car wouldn't start with the Keyless Go. I used the key and the car started, rolled the windows down and then back up and drove off. Apparently driving it re-charged the consumer battery and all was well or so I thought. Typically I don't put it on a trickle charger since I drive it just enough to not need one.
The next morning mostly the same symptoms so I thought the battery had a bad cell. Took it out and had it tested and was good. I was a little disappointed since a 200.00 battery was probably going to be my least expensive solution. Over the next couple of weeks I performed various experiments with the multimeter tool, charger and trunk open and closed. I even had the trunk open and simulated it being closed by manually engaging the latch. I have an Innova 3160D code scanner tool and it did not pull up any codes.
The bottom line is that when the trunk is open there is a normal drain on the battery. When the trunk is closed the battery will lose 2-3 volts overnight or in 8 hours or so. I'm hoping someone can help point me in the right direction or provide insight as to what is coming on when the trunk is closed. Not sure of the sticky on the slow close trunk repair will help but that is the next step on my troubleshooting adventure to see if there is a leak that could be making the pump come on-although I am in the garage a lot and have not heard anything come on.
Thanks for reading this. Any help will be appreciated!
Thanks,
Bo
