Reversed audio through glovebox socket (2011 S212)

[ChiefTech]

Hi All,

I recently discovered that the left and right audio channels are reversed (left channel content comes out of the right channel & vice versa) when playing music from my iPhone. I've had my car over a year and never noticed until I added a track with very noticeable placement of instruments!
I visited my local dealer who wasn't overly helpful and then went on to try to get me to book in to pay for diagnostics which I am not prepared to do as this is obviously a physical error somewhere and not a fault that has just occurred.
I have also tried playing audio through the 3.5mm jack adaptor cable and this too is reversed. Having looked into the connections in the interface cables, the audio line-in to the car uses a different connection on the glovebox socket for the 3.5mm jack lead and the iPhone cable, so I'm now leaning towards the fault being on the car side rather than the interface cables as it's less likely that they are both incorrectly wired.
In the meantime, I have now opened up the connector on my iPhone interface cable and physically swapped the left and right channels over to correct the problem! At some point I will pull out the head unit and investigate further, but I am just wondering if anyone else has had this problem?

 

[ash59fifty-uk]

Can't say I've noticed. I'm tempted to jump on fruity loops and test this for myself

 

[MancMike]

Wouldn't it be easier to just pull the socket out of the glove box and swap the cables on the socket? A permanent, hidden fix?

 

[ChiefTech]

It might come to that. Is the glovebox socket wired directly to the head unit or is there another interface in between? There's two separate line-ins in that socket as the iPhone/iPod cable has the audio on different pins to the 3.5mm jack cable. There's nothing stopping me just swapping the pins in the jack cable now either and leaving the car alone completely! Just thought it would be nice to make it right properly or at least find out if mine's an isolated case before I ring MB customer services.
My car has the factory Audio 50 APS upgrade so whether the problem is only related to that remains to be seen. My local dealer only looked at plugging my phone into one of their new cars, but as they're now all USB it wasn't any use. I suggested trying Bluetooth audio or looking for a used car on the forecourt with the appropriate socket but they weren't interested in doing either!

 

[bnam]

I had read another post where the poster had come across swapped audio wiring in the factory harness.

 

[David404]

Think I'd make up a crossed over connection cable to avoid the need to dismantle anything in the car.

 

[bashers]

check out my post on factory faulty leads:

http://www.mbclub.co.uk/forums/electronics/207063-w219-cls-supplied-faulty-aux-input-factory.html