Mika83

So guys, i'm new around here and a new CLK owner (as of last week), so bare with me ;-)



So, my new car (2000 CLK320) came with the MB phone system installed, and an ugly old Nokia phone cradle on the dash that obstructs the air vents and buttons on the middle console. As i dont have any use for this in car phone i decided that this cradle must go and after 1hr of thinking about how to get rid of it in the easiest way i just cut the two cords that run to it from beneath the dash board.

Now the cradle is out of the car, but i have no sound whatsoever in my stereo! Everything works as it's supposed to but there is just silence from the speakers, and i did push every button on the stereo at least three times so it must be something more delicate than that.


What can this be? Do i need to remove the cable completely from it's socket (i guess it sits at the back of the stereo head unit) in order to get the sound back?

I feel pretty stupid for just cutting the cord, so please bear with me and help me out here..

Thanks in advance,

UK-C200

Kinda silly question, but is it possible one of the cables you cut was orange and actually fiber optics?

I'm not completely familiar with the phone setup in the CLK, but it sounds like one of two things - and post pictures of what you cut..

1] D2B / MOST fiber loop not closed
2] MUTE signal held to ground

Mika83

Thanks for the input UK-C200, it's much appriceated!



I will take photos and post them here as soon as day light breaks tomorrow. I do doubt that i would have cut the fiber optics though, as i can only see regular copper cables plus the phone cradle looks like some generic Nokia setup, so i would be surprised that a fiber optics cable runs into it. Being something that holds the stereo on mute i can very well imagine, as i hear nothing from the speakers even though the functionality otherwise is 100%.


If anyone else has any more thoughts about this please post it here; it will be very much appriceated!

Thanks again!

Mika83

I didn't manage to get a photo of the cut cable/s, but i am sure that it is not an optical cable that i cut; i can count 13 copper cables plus the 2 in the power cable.

My dad had the car today and said that the stereo did sound when he put the car in Neutral..this is getting really wierd!

I am assuming that the stereo/D2B loop is getting some sort of interference from the cut phone cable/PSE, and that it puts the stereo on mute because of it. Anyways, i am taking the car to the dealership and have them take out the phone arrangement completely..

Diesel Benz

If it is an after market Nokia kit, the only reason for no sound I can think of is the mute wire as UK-C200 explained already.

Didn't you find the actual phone control unit, if you unplug it properly, the mute wire should be released. Of course you could try to find if the mute wire goes to the radio connector and disconnect it from there too.

Doens't the head unit indicate "mute" some way?

Another option is that a fuse is blown but I understood your HU display works fine etc.

Mika83

I didn't dare to start pulling wires from the back of the HU (I just removed the plastic container underneath it and peeked inside the panel), but i suspect that if i were to unplug the remaining phone cable properly the sound would probably come back. I just dont dare to casue any more trouble since it looks like a snake's nest of cables and wires behind the dash.

The only way the HU shows that it's muted with the mute button is a red led that lights up, it does not light up for me now though. But then again i dont know if it is supposed to do that when the phone mutes ut, or if it lights up only when you push the mute button physically.

The fact that my dad said that the sound came alive when he put the car in Neutral bothers me a little bit..it just sounds so strange that it would do that. But perhaps the phone 'computer' (PSE) has some kind of connection to the gearbox, i really dont know.

UK-C200

Mika - dealer is probably your best bet if you are not comfortable tracing the wires you cut back to the telematics control unit and unpluging them (and the control unit as well).

I just don't know enough about the telephone setup in the older CLK's to know what's involved, but I agree that it's odd that the radio worked in neutral - but again, if it's a mute clamped to ground or a shorted wire, could just be coincidental that it happened to work with the car in neutral..

Thinking about it, it could be something as simple as the fact that when you cut the wires, the tele-control unit is expecting some type of signal back from the bracket/harness, and is "hung" because it's not getting signal - and MB's are famous for holding the whole audio system down if any device on the ring is unhappy. I strongly suspect if you just traced the wires you cut back to the control unit, and unplugged them, it would start working again...

Best of luck, let us know what they say!

Diesel Benz

The case is a bit confusing in the sense that it is not clear to me if the car had an after market Nokia phone kit or an MB OEM phone kit (that too would be from Nokia but a different setup). Have you looked from the CAR VIN if it came with an OEM phone kit?

Since the mute wire is an "open collector drive pull down signal", an un-powered but connected control unit would likely pull the signal sufficiently to ground, making audio muted. The neutral gear issue sounds strange, it could be that it just made a small voltage change and the pull-down was temporarily too weak.

Mika83

Diesel Benz,


I think it's an after market installation since the phone cradle was very unconveniently located in the middle of the dashboard, obstructing one of the A/C air vents and the buttons for driver's seat heating and head light washers. The cables to it run through a small opening in the centre console.

I am starting to think that it would be just be easier and cheaper if i try and disconnect the unit completely from the system myself; i guess i'd just need to locate the PSE unit and unplug it from the D2B loop (or just disconnect the remaining phone cable from the PSE).

Does anyone here know exactly where the PSE unit is located?