[Joseph Irvine]

Hello,

I have a 2013 Cabriolet, gasoline.

When I turn the key off there is a period for maybe two or three minutes where the lights will just flash on and off very quickly. It is sporadic, doesn't seem to be on a pattern. After a few minutes everything is just fully powered down and it doesn't happen anymore. Just some sort of short period after turning the engine off and pulling the key out where it is in this state where the lights will briefly flash.

I uploaded a short video to YouTube that shows the issue:

Any clue where to look? Is this something simple like a bad fuse, or something I need to have the shop dig into, like an electrical relay or other more major concern?

Appreciate any feedback!

Joseph

 

[litlun]

I've never seen that before so i'm just guessin' but that looks like a capacitor discharging to me, you don't have a big stereo installed do you?

 

[jzchen]

Wow. Can’t think of a reason. Have you tried disconnecting the negative battery cable and reconnecting to see if it goes away?

 

[jzchen]

Anything aftermarket installed? When did it start? Did it just start all of a sudden???

 

[Joseph Irvine]

Nothing aftermarket, still the factory OEM stereo.

Just started out of the blue. First noticed it about four months ago or so.

Just had it in to the Mercedes Dealership for the 50k service. They didn't spot anything in their quick diagnosis, but said they didn't have time to do a full electrical diagnosis breakdown on it. Still, though, obviously not low hanging fruit otherwise I think they would have caught it.

To me it sounds like a relay clicking. You can hear something very mechanical clicking each time the lights blink. However, that could just be some other mechanical part that is getting electricity sporadically; I don't know.

Thanks!
Joseph

 

[jzchen]

The main bunch of relays are located within or next to the SAM, driver footwell up on top, just in case you haven’t heard of SAM yet. Fuses are visible on it....

I find it very intriguing that the signal indicators are NOT blinking as well.

It is not the easiest to access but I would start by trying to drop it down for a visual inspection for any clues.

After a little while the SAM does go to “sleep”......

Will pop back in if I come across something more.

Jesse

BTW- I really enjoyed the metronome synchronization videos on YouTube! Thanks!!!