CME4BENZ

Hi guys,

I have a 1991 300CE with factory radio. I have a Kenwood head unit with CD that I want to install. I pulled the factory radio and there are way too many connections and wires to make any sense out of it. I got a wiring diagram that I think is correct but it is still impossible to figure out which wires are which. The original radio has wiring to an auxillary fader and an amp. I would like to eliminate these and wire the new radio directly to the (6) factory speakers but I cannot determine which wires go to the speakers (how can I bypass the amp and fader?). Any insight from someone who has "been there" would be appreciated.

chupper

Well, I've been there !
First off, you do want to bypass the fader (in the center console). This is just annoying. I installed a Sony head unit and I left it connected to the car's fader. Dumb move.
To bypass the fader, you basically have to rewire the car. You might be able to figure out which wires run where and connect them, but that could take hours just to figure out. It's better to use new and higher quality cables.
Try contacting the company you bought the head unit from for help for your 300CE. When I used crutchfield, they were extremely helpful in getting the car wired and running. They gave me an adapter to plug into the wires from the car which runs to the wires on the head unit. Keep in mind that there are other connections other than speaker connections. My head unit was compatible with the following from the car....
-A 12-volt power antennat trigger wire
-an illumination lamp wire (Tells the head unit when you turn on your lights so it can dim the screen on some head units. To other head units, it flips on a light)
-A ground
-A power connector
-An accessory power connector (tells the head unit when the key is turned to accessory only

Good luck, and consider getting new speakers while your at it. They can be a beast to install, but the sound quality increase is well worth it!

Just email or reply if you have any other questions!

CME4BENZ

Thanks for the post. What a hassle. I actually work at a Mercedes dealership and have asked a few of the techs. They all said to take it to a stereo shop. I spoke to Crutchfield, they are sending the adapter for the power / ground etc. but suggested running one set (front or rear) of wires to the fader and using the fader in the car, eliminating 2 of the 4 outputs in the new head unit. This made no sense to me. As you suggest, I could bypass the factory speaker wiring altogether and run new wires ( a hassle that I was trying to avoid). The new head unit has 4 speaker outputs and the car has 6 speakers. Do I run new wires to the front speakers and then run the rear speakers to the fader in the car to modulate between those 2 sets ?

chupper

Crutchfield is a great company, don't get me wrong, but don't listen to them regarding the fader, unless you like the fader. Bypass it! New wires would be a big hassle, but its worth it. I would rewire my car in a second, if I had time ! The only big reason you should use the fader mechanically, is if there is a problem with the number of speakers and speaker outputs on your head unit. My head unit has 6 outputs, so you could be in a bad fix with your 4 outputs and 6 speakers.
Good luck!

Jimmy C

hey CME4BENZ,

chupper's right!! i just tried to replace the factory head unit in my 93 300ce. crutchfield promised me i could do it with the existing wiring. i had a mercedes specialist remove the head unit to prevent cracking the dash, and wow it looked like a plate of spaghetti behind there. i eventually got realistic and brought it to a car stereo installation specialist. he spent two days on the car. he finally rewired all 6 speakers and was happy to give me the car back. it was worth every penny i paid him. he did bypass the fader, as the aftermarket head unit had one, and it simplified the installation.
well, good luck and enjoy your ride......

-jimmy c

Jimmy C

also, i had four outputs on my head unit. he split the front two outputs to the front four speakers. i left the factory speakers and am quite impressed. good luck!!!

-jimmy c.

chupper

I'm glad JimmyC said what he said. I guess you can split the four speakers to two outputs.

He said he took his car to a stereo specialist person. Not a bad idea if you don't have time.

I previously had NO knowledge of car stereos (although I know a lot about in home stereos and electronics in general). It did take me the whole day and another half day to get it installed properly. If you don't mind spending that amount of time it can be fun and frustrating and entertaining and a learning experience. If you don't want to spend the time, pay someone to do it.

Either way, bypassing is worth it. As I said, I have yet to rewire. Keep in mind, it doesn't matter how and where you lay the wires ! As long as they get to the head unit and speakers, your good. For removing the dash, look for some pics in this forum, I used the info here.

After removing my entire center console, I laid it on the ground. A few hours later I proceeded to drive the car over the nice wooden center console. To make a long story short, I used some black tape to cover some of the cracks and you can still see some. I must say though, that wooden console held up well, considering the weight of the car ! That was a stupid mistake, but I have so many electronics in the car, most people don't even notice the small cracks in the wood. Stupid mistake.

Well, anyway, good luck again!

CME4BENZ

I had the head unit out again the other day. I looked it over with the wiring diagram in hand and one of the MB technicians here at the dealership. For the third time I was told to take it to a installer that does work for us. I am finally going to listen and have him put it in for me. Thanks for all of the insight. I just don't feel like spending a couple days on it.

dlafever

OK, let me see if I remember ( having replaced the head units in all of the MBs I have owned, what crap):

Find the connecter that plugs into the back of the becker head unit. With great precision, cut the dam thing off. It is useless unless you plan to install another becker OR use the harness adaptor from Cructhfield. Wiring is actually quite simple, you will notice that each of the wires carries a max of 12V DC. So get out your voltmeter:

Brown - always ground on an MB ( I use this to connect the Neg side of my meter)

12V always To battery
12V ignition ON, 0V iginition OFF Accessory
12V headlights on, 0V headlights off Illumination
Single Blue ( I think ) wire Antenna (needs 12V from head)

There may be one other wire, which is the speed sensor for volume adjustment. I first saw this on my 1990 500SL, so I doubt that many E-Class cars would have it before 92 or so.

As for the speakers, bite the bullet and rewire directly to them, the fader sucks unless you listen only to AM. Also, the fader fails about every 5 years or so, just disconnect/bypass it for better sound.

By the way, I understand from my local parts guy that the Becker is worth a little bit to a radio rebuilder, so you may want to find one an offer yours...

A nice Saturday project is to remove the seats and carpet and clean the carpeting with a pressure washer. Takes all of the previous owner's indescretions out of the natural German smell of your car. While you are at it, run new speaker wire to the rear speakers.

-Dennis

pkmaven

Chupper is right on-avoid the oe fader which is wired to handle only 50 watts rms. (the 500E has a different fader that handles 75 watts). Your new, cd head unit has an elecronic fader built in that has much less distortion. Of greater concern is your head unit's output, it's four ohms. The o.e. speakers are between 2-3 ohms. If you are using deck power as opposed to an external audio amplifier, you'll need every break you can get. Replace the front and rear speakers with similar size coaxial speakers (2-way with tweeter). All aftermarket speakers are four ohm. Run new wires to fronts and rears and delete door drivers. The sound should improve greatly. P.

mb300

do you guys have any information about the front door speakers in a 90 300e.

im trying to find the speaker wires for these, i think that there is a factory amp for these speakers in the front doors.

thanks

dlafever

I am pretty sure that there is no amp in the front doors, but one located under the dash or front kick panels. I had the opportunity to gut a newly-wrecked 1991 300E and personally removed the door panels and speakers. The dash speakers in this car had a cap soldered inline with their connector and if the door speaker is anything like what I had in my 1990 500SL, there is simply a 12db/octave choke inside the black speaker box limiting the door speakers to low frequencies.

-Dennis

ZedStyle

I tried searching, but came up with no definitive answers. I didn't want to make a new thread for no reason, so i will ask in this one..

I want to install a new cd player in my car, it's a 95 e320 special edition.

will this wiring harness work? says for a VW, but good ol' 'keith' from crutchfield assures me it is fine.
http://www.crutchfield.com/S-2ttvgqP...1758&s=0&cc=01
will i need the radio antenna adapter as well?

also, do i have a factory amp in the car, and if so, where? I have no fader on the console, and six speakers in the car. sorry, i haven't explored anything yet, i just figured i would ask first.

finally, where can i find a reliable wiring diagram so i can figure out which speaker wire is which behind the dash?

I have installed a few cd players before, just none in a mercedes. I want to work on starting things this weekend... these cars are crazy, each one seems different from the other...thanks!

YNVDIZW124

I don't know if there are such adapters for the w124? What i do is tap into the factory wires to wire up my stereo and still keep the factory harness....on a w124 Power is Grey, Remote is red, and Ground is brown, Power antenna is blue. To wire up the speakers i suggest you use your original head unit and unplug all the connections to the speakers and test one by one and lable them like FRD,FR,FLD,LF,RR,RL...etc or how ever you want. If you don't have any technical or electrical skills i suggest you go to a shop to have this done.

hartj

zed in 94' mercedes did away with the external fader and i believe that it is built in to the deck it self.(similar to a new aftermarket stereo)

ZedStyle

yeah, the fader is part of the head unit...
so does this car have an external amp somewhere, or is it part of the head unit?
i'm pretty set on doing this myself, i guess i will tap into the wires and leave the harness where it is... thanks much!

neanderthal

amp should be in the right side of the trunk behind all the lining. ust pull that aside. the dull grey box is the amp. and in many cases, the radio tuner too.

one thing to consider is leaving the amp to power the door speakers and using the head unit to power the four main speakers.

but chupper nailed it; rewire the car. a tech can do it in a few hours without removing the seats. you can do it in a weekend.

Makahveli

I recently successfully installed an aftermarket radiio a few weeks ago, and now I've decided I wanna run wires and hook up amps, it there a specific tool I need to remove this new deck?

X03

putting in the new headunit should be fine especially since you already have some experience. I did mine on my own with no knowledge at all, and it turned out fine. Just took me a longg time, wont even mention how long. But you mentioned the antenna adaptor and you shouldn't need one. I didn't on my 90 300E. I think the older vw/audis/benz do though.

ZedStyle

argh! it needs an adapter...

dlafever

Zed, just wondering why you think so. I have had many MBs from 1971s to 2002s and never needed and adaptor for the antenna. Is this what you mean?

ZedStyle

well, the radio plug behind the mb radio is a small round plug, and the one for the new radio is the long thin type...
also, the amp behind the seat neanderthal was talking about... is it a black unmarked box with fins and only one plug in it? because that's all i have, and i'm assuming it's the amp, but i was expecting something a little different.. it's bolted onto a brace near the fuel door

X03

well if you did need an adaptor, you can get it at any audio place. I went to get one for a friends VW at bestbuy for 12. Just ask for the female to male antenna adaptor.

Koolwipski

Hello all. I have a 1992 400E and I recently went through the "discovery" process in attempting to install the Alpine aftermarket stereo. I found that there were two amps on the pass. side of the trunk wall right next to the radio control unit. I ultimately took the car to a stereo shop and they re-wired the car (actually removed the amps and control unit - rewired speakers from where they all come from the amps - rewired antenna, etc...) Works great, sounds great. Cost $79 which I thought was a bargain for that job.
I do want to change the speakers out, any ideas of how to get them out of the doors? dash?

ZedStyle

does anyone have a list of what wire is what behind the stereo?

everyone says brown is ground, but what about the others... i think i will be able to figure out the speakers by myself, but i don't have a voltmeter or anything, so i need to know which is ACC, which is the dimmer, which is the constant power...
also, my dash speakers have two connections going to them. i thought i read somewhere that one is a ground, is that right?