MB318

hi to all new GLC owners, I would like to know if there's problem with battery suddenly goes flat when car is park (without locking) the whole day. Has anyone heard the buzzing sound coming from the under carriage when doors are open especially? Does this contribute to the loss of battery power that I need to start my engine to avoid battery drain? Thank you in advance for any answers out there.
ps: GLC250 AMG Line

rbrylaw

I wouldn't park my car without locking it, but I've never heard any buzzing sound from under the car if it's not locked. Certainly no one has come on here saying they're having any issues with the battery draining.

GaryOkie

I've only had our GLC300 a few days and not experienced a battery issue but I have heard a strange electrical buzzing sound that sometimes goes on for at least 30 seconds after opening the locked door. It sounds like it coming from under the hood, close to the firewall.

This buzzing sound may be associated with another strange sound I'm having when the car is off. See the "GLC300 Gremlins" post. I am concerned that this repeating but inconsistent electrical buzzing/whirring/clicking could drain the battery if it goes on and on.

rbrylaw

To give you peace of mind, make an appointment at your dealer and let them hear it.

GaryOkie

well, that's exactly what I did - the car has been with the dealer for a few days now. Problem is, what was a very consistent and repeatable noise issue in my garage, has been completely quiet at the dealership/service bay and can't be duplicated! I did provide them with an MP3 of one of the short loud sounds it has been making, but not this long continuous one. Again, both occur when the car is off.

So I will be bringing the car back tomorrow, to see if it continues to generate these unusual sounds as before or just fixed itself somehow on the way to the dealer. It's a crazy thing.

I only posted to this thread due to the OP commenting on an "electrical buzzing sound" which could possibly be related to my issue.

matttt

Has that noise been resolved or explained? My GLC makes a noise when I turn off that I've read is probably the pumps running to cool the turbo, as well as fans for the LED headlights, and a noise when I unlock the doors, that is supposedly the brakes doing a self check. But it randomly makes noises when the car has been switched off and locked for hours, it sounds like a water pump of some sort running, and it cycles on for about 15-30 seconds, and reoccurs either every couple minutes, or hours.

GaryOkie

hey matttt,

I'm glad you posted this 'cause I was hoping I would hear if anyone else was experiencing weird pump/gear sounds when the GLC has been off for a while.

Yeah, I also sometimes get a long continuous buzzing sound from under the hood when opening the doors. I hadn't heard about the brake self-check explanation, and the dealer couldn't offer any explanations since they couldn't duplicate any of it.

So, while it would be nice to know what self-tests, priming, or whatever the engineers programmed into this car when off, I am assuming for now there is no service issue.

matttt

Hey Gary,
Do you also hear noises intermittently after the car has been switched off for a period of time? Or just right after you lock it?

Penn

There is certainly some electric motor noise whenever I open my doors, even if the engine has not been run for several hours. Have not been able to locate the exact source of the sound.

GaryOkie

Yep matttt, sometimes long after the car has been turned off it will make that loud whirrrr/click, which is not the same as the continuous ~30 second sound when opening the doors. This was the sound I recorded in the other post "gremlins". Haven't noticed it so much lately just because the garage is too cold now to be spending much time out there.

fabbrisd1

Yes - unexplained "noises" - yes - normal - yes - I don't know if anyone really knows what it is - however, on one experiment where we removed the Keyless Start button - in that experiment the noises went away - with key off/removed - the system really/really shuts down.

AS_glc250d

Hi, very new here but same problem more or less. A mysterious battery drain affects ability of eci start stop to function properly. Giving an overnight charge solves the issue for around 10 days, but then back to square one.

Someone suggested i remove key fib from car whilst parked overnight in garage. However i think its that electric sound that occurs that's probably the culprit.