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Discussion Starter #1
Hello.

We recently replaced our 2003 Mercedes E320 battery in the trunk. Since then, the interior lights have lighted up on its own sometimes in middle of day in the garage. It seems to happen only when the alarm is on (i.e. car is locked). The car itself shows that there are "No Malfunctions". What are possible reasons to this symptom?

Note that we did not drive the car for a year prior to the battery replacement because it was outside our budget plus we did not need to drive it most of the time as I take the public transit.

Thank you.
 

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2008 E350
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If your car is equipped, have you checked the auxiliary battery?? I have seen threads on this and other forums where unusual electrical issues can be traced back to a dead or dying aux battery.
 

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99 ML430, 00 ML320, 05 E500 4matic Wagon
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Aux battery is for SBC brakes.
All other electric functions are getting power from the main battery.
 

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Discussion Starter #4
I'm also noticing that this problem seems to occur around 5-6 in the afternoon when the car is locked (i.e. alarm on). Any thoughts?
 

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222.132 & 221.122 & 213.050 & 906.633
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I'm also noticing that this problem seems to occur around 5-6 in the afternoon when the car is locked (i.e. alarm on). Any thoughts?
Sounds weird. Where is the car parked when the lights go on? Could it be from the door switches closing from the traffic passing close to the car, like a big noisy truck or something similar? The door switches are sometimes sensitive and close while the car is driven if the body bends a bit at turns etc.
 

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Discussion Starter #6
The original suspicion started when the car was in the garage at this time. Most recently, I went out around that time to pick up something. On my way back to the car, I saw the lights turn on ... this was when I realized the cause of this is in the 5-6 PM range. Further, it's probably not caused by something near my garage.

Something that might be the cause of this is that because our previous battery was so dead that the car couldn't be jump started, the mechanic at a shop brought a new battery to my garage to install it personally. Since the instrumental cluster shows "No malfunctions", he didn't see the need of taking the car back to his shop for resetting (via his shop's computer). All he did was install battery, and reschyn. windows/sunroof/seats.
 

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Discussion Starter #7
Update: I resolved the issue a couple weeks ago. It turns out the car just needed resetting. For whatever reason, the car's alarm never reset itself until a few weeks ago. Hope this helps anyone who may encounter something similar. :)
 

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2007 ML320CDI, 2003 E320, 2004 CLK500 Cabriolet
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Resetting?

Hi, my E320 sedan has started to have issues like yours. When you said you solved the problem by resetting" it, what did you mean? Thanks!
 

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Resetting here, is probably meant the same way it is used in general, like when resetting a clock or computer: by disconnecting then reconnecting the power supply, in this case, the battery.

Resynching the sunroof involves pressing the open button and press and hold it again, once the roof is in the fully open position.

Resetting windows? I dunno. Resetting to what? No parts to reset or resynching.

The key can be resynched to the vehicle, synchronizing that permission data. (Insert key, don't turn/sometimes can't turn, remove key, hold lock button, while pressing unlock 5 times.) An audible click can be hears when key is inserted, indicating that key is synced into the system. No sound, no key turning allowed.

Interior light flicker could result from a faulty door switch or connection, thus sending faulty signal to computer indicating door is still open and, hence, interior light flicker.

Also, have you checked the auxiliary battery?? I have seen threads on this and other forums where unusual electrical issues can be traced back to a dead or dying aux battery. Or a dying aux battery relay which regulates the transfer of power source between primary and aux battery.

Those 3 are the first items that should be checked when facing electrical issues.
 
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