No Sound from CD or XM. Radio OK. - PeachParts Mercedes-Benz Forum

wjm · #1 06-15-2003, 09:25 AM

folks,

I just installed an Alpine CDA-9815. I made my own adapter using the alpine adapter and an M-Class adapter. I had the pinout information for both the radio and the car's current harness, so making it was not to difficult. Also, I soldered and shrink tubed all my connections.

Here is the problem. When I turn on the radio, the power antenna comes up and music plays fine. When I put in a CD or I put the Radio on XM preview channel, the power antenna goes down (as expected) but I get no sound.

I did not bypass the factory amps, so I'm guessing that somehow the amps are not getting powered in those 2 modes.

Also, the radio has a "remote turn-on" wire which I did not use. Could this be the problem? The wiring diagram show that the amps are powered directly from the "fuse and relay box" via the "sound system feed connector (amplifier - circuit 30)", so I didn't think that this wire would be needed. If needed, where do I hook it up to?

Could it be that mercedes is using the antenna wire to power the amps? The reason I ask is because with the original mercedes, the antenna stayed up in all modes.

Any ideas?

Thanks

wjm · #2 06-15-2003, 02:07 PM

OK,

I unplugged one of the amps and jumped the input and outputs for the left rear speakers. Now XM and CD work. So, looks like the antenna lead is somehow responsible for powering up the amps. Again, Since my antenna is going up and down correctly, I know it's wired correctly.

Is it better to connect the radio's amp lead to the factory amps, or will it be better for me to just take the factory amps out of the mix?

SCLJA · #3 06-16-2003, 03:49 AM

If you isolate the amp and antenna trigger wires and hook them up to the blue and the blue white then your antenna won't be up all the time. You will find the antenna wire is a blue wire in a black vinyl tubing @1/8 inch in diameter and the amp turn on being either one or two black wires about a foot down on the radio harness if I remember correctly.

Scott

wjm · #4 06-16-2003, 08:49 AM

Do you recommend that I use the factory amps or just jumper around them (which I can easily do, since I have the wiring schematic)?

Anyway, my antenna is not up all the time. It only comes up on Radio, and not any other mode (CD or XM). This is the way I like it. The Becker radio always had the antenna up in CD mode... I hated that.

OK, If I understand you correctly, you're saying that about 1 foot up the harness, the amp's trigger wire (black) is tied into the antenna trigger (blue), right? If I separate them, then and hook the radio's amp trigger wire (blue/white) to the black wire, all should be well, right? I think this will be tough without taking out the entire console.... but what the heck.

Let me know if I'm on track.

Thanks!

Scott

wjm · #5 06-16-2003, 11:16 PM

Well, I'm finished. Everything works fine now by simply not using the factory amps.

#6 06-16-2003, 11:20 PM

Scott

You're on the right track.

The radio has 2 trigger wires. One for the antenna and the other for amps.

Looks like your amps are tied to the antenna trigger wire.

Separate the wire for the amps and tie it to the amp trigger wire from the radio.

Let us know how it goes.

Good luck.

wjm · #7 06-17-2003, 12:02 AM

Maybe I misunderstood.

Correct me if I'm wrong... in my vehicle, the radio (Becker 1492) only had an antenna trigger... no amp trigger.

My guess is that in order to trigger the amp, Mercedes used the antenna trigger to turn on the amps... which explains why the antenna was always up... even in CD mode.

If I read Scott's post correctly, the amp harness is connected to the antenna harness somwhere down the harness... but I cant seem to find it.

Do I have this right?

#8 06-17-2003, 04:29 AM

Oops...sorry Willy, I got the names confused.

Btw, I'm just fresh from installing a Lanzar amplifier to my Kenwood Receiver/10 Disc changer.

On my Kenwood, there are 2 feeds - antenna and amp.

With only one feed on yr Bekker set, it would look like the antenna always has to be up, even in CD mode...that sucks

.

Hope Scott can help you with this one.

Good luck.

SCLJA · #9 06-17-2003, 09:54 AM

it wont matter any more how you configure it if you are not going to use the factory amp/s just hook up the antenna wire as you have done and go ahead and wire past the amplifiers.

Scott

wjm · #10 06-17-2003, 10:00 AM

OK, that's what I ended up doing. Thanks!!

Is there any advantage hooking up the factory amps?

Anyway, I just wanted to know how to do this for completion of the thread. Sure someone might want to do this in the future.

Willy