New radio questions?

[CarreraDan]

Guys,
I got a CD player for the Mercedes (82, 300DT) for Christmas and went to install it today and ran into some problems. First, it was mucho fun getting the old radio out (Becker Europa) finally got it after trying about 1000 different things. Next is the wiring or lack there of. There is a fused black wire going to the back of the radio (I assume this is power), two sets of wires that are green/black and red/black (speakers), and then a large black wire with a spade connector--no clue what it is, and finally the antenna and a brown wire (ground?). Does anyone know how to connect my new stereo with 2 wires for each speaker to what is behind the old one?

Would it be easier to start over and run new wire? Should I just get used to the Becker that works fine other than adjusting the tuner by itself when you go down a rough road? I know I could get the radio installed at Best Buy or Circuit City but I have had bad experiences with both places hacking up stuff and would prefer not to mess up what I have in the Benz. Thanks for any help.

[techguy512]

I ran all new speaker wire. This left all the factory wiring in place, and completely bypassed the weird factory center console fader setup.

I don't think it's possible to get independent front/rear operation with the factory wiring.

[hangit]

Check with Hutchcraft. They have wiring harnesses for new radios using the stock wiring. Downside is it will only be 2 channel, not 4. I've got one coming for my 83 300SD.

John

[winmutt]

black is + brown is -

run new wiring.

I ran new wire straight from the stereo to the rear speakers leaving the stock harness in place. My center console is the black plastic so I was able to remove the fader and plug it's hole with blank out cover from a 2-speaker (no rear speakers) 240D.

Does this help?

[CarreraDan]

Thanks Guys,
I really apperciate the feedback and wiring diagram. I think my best bet will be to run new speaker wire and just start over with the whole fader thing. I will most likely just leave everything in place and run new wires for my new radio--just in case I ever need to put the old one back in. Hopefully, Monday it will be warmer and I can get this finished as working today in 20 degree temps wasn't much fun.

[Jeremy5848]

I also ran all new wiring, abandoning the factory wiring in place (that way, my mods are reversible). With the factory fader control no longer needed, I used the switch position for a garage door remote switch (there's a write-up on the forum somewhere).

Jeremy

[bulletproofair]

First off pull up your center console wood piece. The one with the window switches. Afterwards you'll notice the fader switch and all the wires going to it. By looking at it and using your brain you'll be able to determine which wires are coming from the speakers and which wires are leading to the radio.

There are 8 wires leading to the fader and there will be only 4 wires leading to the radio. This is because there is a common ground for all positive wires (from what I think I remember). Because of this there will be 4 wires ( + for each speaker since ground is common) leading to the original radio.

After determining which wires are coming and going from where you'll be able to determine where to cut the wires in order to cut out the fader to determine where to splice in 8 new wires in order to make each speaker singular. These wires should run to the center console where the new head unit will go in order to splice in your new wiring harness.

After figuring out which 8 wires are the speaker wires that are running to the fader you can take a AAA battery and put the + and - wires on each end of the battery to determine the location of the speaker in question so you can splice in your new wires for your new harness accurately instead of guessing. By matching up the corresponding - and + wires with the AAA battery you can do this entire installation with no color code guide or anything but on testing alone. It's intimidating to the everyday installer but with some confidence and a little common sense you can figure out which wires are which and then figure out which wires go to what speaker with the battery test. If anything you can just simply rule out which wires go where by just holding a + speaker wire to the + of the battery and test each - wire and when you get a fuzz out of a speaker you will know those two wires correspond to the speaker the noise is coming from.....hope that is explanation enough....

Use the ground wire that was spliced into the old Becker with the bolt as your ground source.

Good Luck. Its really not that bad to figure it all out.
- James

Post up results and questions if any as I have much experience with this. Also I am in the process of installing a new head unit on my newest Benz so I am in the midst of going through this all on my own again.

[CarreraDan]

James,
Great idea, thank you. Now I am getting excited about working on this the first part of the week. I have had the center console out before so splicing the wires in at the fader should work very well. I really wish I had time over the next two days to take care of this but I have to go out of town. Thanks again everyone for all your help.

Daniel

[anthonyb]

I'm not sure if this also applies to your W123, but in the early W124's with the one-piece radio, the wires for the front speaker run forward and plug into the speaker harnesses just behind the radio. If you end up not wanting to run new wires, you can tap into the front wires here. Connect the rear outputs to the wires that run to the fader, and just run the rear channels through the fader control (leave it in the center position - this should be a metal-to-metal contact that will give you better SQ).

This way, you get full fader control through the head unit, but without having to pull out a bunch of interior trim and running new lines.

[Dee8go]

Originally Posted by winmutt

black is + brown is -

run new wiring.

New speaker wiring? So, you're saying to use the existing wiring for power and ground, but run new speaker wire? Then this will just bypass the console fader completely, right?