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I needed to wash my car and so I took it through one of those automatic car washes. So the wash finishes up and I'm driving out of it, and all of my speakers start making crazy cracking, hissing, and thumping noises (especially the back speakers). It makes those noises for a few minutes and then the speakers stop producing any output whatsoever.
This has happened to me twice before, when going through an automatic car wash, but those times the sound came back after abour 24 hours. This time the sound has not came back (it's been 2 weeks). In all instances the head unit is still functioning properly, the only problem is that there is zero output from any of the speakers.
Has anybody experienced anything similar before? Any advice from you Mercedes Guru's in here?
Thanks in advance.
*random picture of my car, for sake of content.
Last edited by FIREfreezerC250; Oct 9, 2023 at 12:07 PM.
@JettaRed Since the audio came back the last 2 times, I thought it would come back again... Yes, admittedly that is a dumb way to go about it. I will not be using auto-washes again. Not really the advice I was looking for though...
@TimC300 Thank you! Those diagrams are very helpful. I found the fusebox in the trunk on the right, but I didn't see the power amplifiers on the left side. I'm going to take a look at the amp and stuff, but besides a blown fuse, I'm not sure what else I should be looking for.
@Odd Piggy Lol yes that is indeed a cloudy day in AZ.
I havent touched the stereo in my Mercedes but in all my previous cars I always installed installed complete systems from head unit, amps and speakers. I did start looking in to installing one in my Mercedes but it doesnt look that easy, even the speakers in the door look like a project just to replace.
if i wasnt getting sound from my stereo i would start at the speakers and trace everything back to the head unit. Get my multimeter out and start testing. Is the speaker getting power, probably not so trace it back to the amp, is the amp putting out power? If not find where the powers going in to the amp and see if it is getting power, if no then trace it further, but if its getting power then it may be the amp.
If I were you I would try to be locating the wiring diagrams for your specific car. I know there are all types of different components in these cars depending on what head unit is in there.
Theres a few fuses in the trunk that are related to the amps and stereo. Like #67, #69, #81.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Building on what Tim said, there are at least two separate control modules associated with the radio and COMAND units. Do you have a good scanner? You should at lease check for codes. Here's my list of good, relatively inexpensive scanners.
iCarsoft MB V3.0 (not MB II)
Launch Creader Elite Benz
Foxwell NT510 Elite
Last edited by JettaRed; Oct 10, 2023 at 07:41 PM.
@TimC300 Thank you for the information, those fuse diagrams are very useful.
@JettaRed The only reason I haven't bought a DTC scanner yet is because there is an AutoZone literally across the street from my house and they always have one I can use for free. I really should get my own though, because I think the Mercedes specific ones give you more information.
UPDATE: So I got in my car to leave work on Friday, and my speakers started working! Out of nowhere! After a month of them not working they are back. I am glad they work again, but I am very confused as to what happened. Like, what changed?
Anyway, I notice the front ones sound like they are blown, there is high-end cracking and they just sound blown (probably from all the hissing and popping they were doing after whatever it was that got wet).
Last edited by FIREfreezerC250; Oct 29, 2023 at 02:44 PM.
Reason: typo
Probably water and they finally dried out. I have solar powered motion lights around my house and sometimes during heavy rain storms they start acting funny, sometimes stop working. A day or two later they mysteriously are working again.
I would try and investigate where the water is getting in from. I know theres hoses for the sunroof drains that empty out under the car at the rear bumper, may be another in the front. Check to se if those are blocked. Check the trunk lif gasket.
did you figure out the problem? i drive a 2012 c250 coupe and this happens anytime i use an automatic carwash, touchless carwash, hand wash, and even heavy rain.
This happens to me too. I’m currently waiting for my speakers to start working again from Friday’s carwash. We shouldn’t have to avoid the carwash. There has to be a way to resolve this issue. Why does this seem to be a MB issue? I’ve never had this happen in any other cars over the years.
Definitely water damage. You need to check inside cover panels in the trunk and spare tire storage. Check water leakage by feeling all the carpets cuz it's getting in somewhere.
On my 14 c300 with there Harmon karden system the amp is in there left side of the trunk behind the cover panels. Very close to where there trunk hinges go down
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