Dead Battery

Aug 21, 2024 | 09:05 AM

RWmorey

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GLC300

Dead Battery

We left the sunroof open in our 2022 GLC 300 and unfortunately we had heavy rain that night. The car battery now seems dead but when we opened the door with the key the alarm blasted and the interior lights go own when we open the doors.

I have connected a slow charger to the battery but I'm confused as to why the battery would have died over night. Could it be from the rain? Or would leaving the sunroof open some how have caused the battery to drain regardless of the rain?

Thanks

Rich

Aug 21, 2024 | 11:41 AM

RWmorey

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GLC300

Ok I spoke to my mechanic and he suggested all the electronics in the cab may have caused something to get fried from all the rain. But he did tell me I was the second person who left their sunroof open.

The slow charger did charge the battery but the car is still dead.

Rich

Aug 21, 2024 | 02:05 PM

RWmorey

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GLC300

So our mechanic things is possible the water caused some "module" to short circuit. Unfortunately they can't take the car until Saturday so in the mean time we'll keep testing to see if it dries out and comes back to life.

Aug 21, 2024 | 06:34 PM

wireman218

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2022 GLC 300 4 MATIC

Quote:

Originally Posted by RWmorey

If possible, use some fans to help dry things out. Throw some desiccant in the interior also.

Aug 21, 2024 | 06:41 PM

RWmorey

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GLC300

Hi --

We did suck a bunch of water out with a shop vac and the car is fortunately sitting in a warm sunny spot so hopefully it will dry out.

I will look into getting desiccant also.

Thanks

Rich

Aug 21, 2024 | 07:52 PM

mikapen

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From: Colorado

'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan

I think I'd notify my insurance company. You may have some expensive damage that could be covered by comprehensive insurance.

I would be concerned about hidden damage.
Let's hope that a thorough drying fixes everything.

Aug 22, 2024 | 10:35 AM

RWmorey

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GLC300

Hopefully drying it out fixes it. So far it still doesn't start but since the mechanic can't take it until Saturday we have more time to let it dry out.

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Aug 23, 2024 | 09:22 AM

RWmorey

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GLC300

We put rice in the car yesterday. How long would you expect it to take for the car to dry out? We did not realize the sunroof was left open until Tuesday - it rained heavily here on Sunday night. We did shop vac out a bunch of water so today is day three of letting the car dry out.

Also, I have attached a trickle charger to the car but it indicates the battery is charged, however there are no lights or anything working in the car although the horn "alarm" did go off when I opened the hood.

Are there other steps I need to take to try to "reboot" the car other than letting it dry out? We are trying to determine when to give up and bring it to the shop.

Thanks

Rich

Aug 23, 2024 | 10:03 AM

#10

sn202020

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From: Canada

2017 & 2022 GLC 300 4Matic

I would check fuses in the 3 locations.
-under the hood.
-Left side of the steering wheel,
-trunk.

check obd code with a reader
Remove most fuses
insert one by one & find shorted circuit fuses
etc.

Last edited by sn202020; Aug 23, 2024 at 10:04 AM.

Aug 23, 2024 | 10:21 AM

#11

RWmorey

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GLC300

Ok thanks. The screws on the fuse box in the engine compartment appear to be torque screws. Is there a tool in the vehicle to remove the screws?

Also, is it possible to open the back lift gate manually? Since the car is "dead" I can't pop it open with the key FOB.

Thanks

Rich

Aug 23, 2024 | 10:55 AM

#12

sn202020

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From: Canada

2017 & 2022 GLC 300 4Matic

Quote:

Originally Posted by RWmorey

if you don't have torque bit, don't know how to use a multimeter, then you need someone to help you i guess.

Sorry I don't know how to open the rear gate without the battery power.

Aug 23, 2024 | 11:13 AM

#13

RWmorey

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GLC300

I do have a torque attachment for my drill so I was able to get the screws loose in the engine compartment, however, I do not have a multimeter.

I think at this point we will just bring the car in for repair and give up on hoping it would dry out and work again.

Thanks

Rich

Sep 3, 2024 | 05:27 PM

#14

RWmorey

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GLC300

So the car is dead. We had it flat bedded to the dealer and they could not "talk" to the car so I called insurance and they totaled it. So now we're on the hunt for the same model because we really liked that car and only had it for 10 months. Fortunately my wife is not killing me over leaving the sunroof open.

Sep 23, 2024 | 06:49 PM

#15

RWmorey

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GLC300

Just wanted to give everyone an update -- The insurance company did total the car and we bought basically the identical car which we just took delivery of today.