I have a 1990 300E 2.6L engine and both rear speakers are not working. I had the original Becker radio and the rear speakers were not working even though the fader switch in the center console seemed to work. When thw switch was in the middle position or the rear position, the speakers don't work.

I thought it was the head unit so I replaced it with a JVC radio with four outputs for speakers. I used a wire conversion kit and wired the speakers directly and by passed the center console fader switch. The rear speakers still don't work. I haven't pulled out the speakers to test them but it seems odd that both rear speakers would be blown.

Any recommendations on what the probelm may be? Thanks.

Check if you are getting power at the rear speakers. You can go from there...

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J.H.
'86 300E

It is possible that I did not bypass the fader switch properly. Does anyone know how to bypass the switch to get the rear speakers working? Thanks.

splice the wires or run new wires to the rear speakers. Start witht basics. Are you sure you new radio has the farder to all 4 speakers? Are you connections OK? Did you exercise your farder control back and forth a few times. The console control are notorious for getting all kind of dirt and liquids under there....

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J.H.
'86 300E

Yes, I checked all the connections and everything else works fine on the radio. The radio does have a built in fader so I don't need the center switch. I clean and tried the center fader and I still don't have rear speaker sound. I would just like to bypass it but I don't know how? I don't want to run new wires to the rear speakers since that's more complicated.

the resources tap on top of this page?

I found this link there:

http://www.peachparts.com/Wikka/W124Stereo

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J.H.
'86 300E

The Mercedes supplied speakers are of a non standard resistance (6 ohms) and quite a low power value (10 watts). Any modern amp will overdrive these speakers and either damage them or just give distorted noise. To add insult they are not even standard physical sizes. Some small mods will be required to install normal sized off brand speakers.

If you require a good sound system then replace the speakers and the speaker wiring. Further, the original wiring is quite thin. Further, if you are installing a higher output power head unit/amp run a new fuse 12v power supply for it.

Modern head units have built in rear/front faders so the original MB pot in the console can be bypassed.

Thanks for the recommendation. I didn't replace the head unit with a good radio. It is a very basic radio so I am fine with the rear standard speakers. How do you bypass the center console fader switch? Thanks.

The wires to the rear speakers start at the console fader. You need to pull your console apart where the window switches and fader control are to identify which wires are which.

After reading your original post its seems like the rear speakers have never operated - even when you had the old Becker in it. You have checked to see that no one has removed the speakers? If they are there, remove the grills and remove the speakers and make sure they are plugged in. There is a fly lead connector plug on the speakers that connects them to the wiring that goes away to the fader control.

Check the colours of the wires that go from the speaker to the fader control. Identify the wires at the fader control - preferably by using a multimeter. Using the multimeter will make sure that there are no breaks in the wiring.

Even though you mention that you have bought a pretty basic head unit you need to know wether or not it has four outputs (front L,R and rear L,R) or two outputs (L,R)
If you have four outputs then you will need to join (extend) the rear speaker wires to the output position on your head unit.
If you only have two outputs (L & R) you will still need to extend the wiring from the fader control and parrallel them up with the front speakers. (not really desirable)

Great advice! I will definitely try the tests you recommended and hopefully it will work. I know that the rear speakers are in the car and that my new head unit is four channel output. It seems that I bypassed it incorrectly and I will check the wires by the fader. Thanks again!

Two misnomers:

Low-watt speakers will be destroyed by a powerful amp.

Factory speaker wiring is of an insufficient gauge to power the speakers effectively.

In a word, FALSE!

Modern amps and head units can easily handle the odd-ball resistance loads of a wide variety of factory speakers...we aren't limited to the 8 or 4-ohm standards of previous decades. The finest car amplifiers can even tolerate a .05 ohm load!!!

What destroys speakers is insufficient power, due to an amp that reaches it's power limits begins to clip signals into square waveforms...which, for prolonged periods will heat up the voice coil and ultimately kill the speaker.

This amp for instance is providing the power for my factory speakers in my 300E...if the rated 1400/watts/ch is accurate, it has been cranked up to the max allowed by the head unit with NO complaints from the speakers...



For most applications, 16 gauge speaker wire (generally sold anywhere) is more than adequate for regular speakers. Audio output signals carry a relatively small voltage, so welding cable is not needed...subwoofers included!

Below is the speaker wire used for the trunk-mounted sub...despite the thick insulation, this is 12-gauge wire.



Power leads are a different story though...the high amperage load demanded by high-powered amp, dictate thicker wiring...below, the amber cable is the 4-gauge power lead from the battery, while the red/yellow cables are 8-gauge to the power amps. The distribution block below feeds the ground cables.

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

So this means that I must disregard the precautions in the installation manual for my high end Pioneer head unit (22 watts RMS per 4 channels) and the installation manual for my Alpine amplifier (60 watts RMS per 4 channels) which mentions that the speakers must of sufficient rating to handle the output power - otherwise some damage may occur.

Your $ 85.00 Crunch amplifier is rated at 1400 watts @ 1 speaker 2ohms. or 175 watts per channel with 4 x 4 ohm speakers. All peak to peak values. 4 x 6 ohm speakers will be something like 110 watts per channel peak to peak or something like 70 watts per channel RMS. These values are for maximum volume. According to the marketing speil the Crunch amp figures are rated as "Dynamic Music watts" - what ever that means. Benz speakers are rated 10 watts RMS and according to which release market are high quality.

Specs from here http://www.cardiscountstereos.com/catalog%20page.asp?Product+%23=P14004

The speaker wires from the fader control to the rear speakers are around .4mm - enough for the "standard installation". The Becker audio units and general audio setup of the seventies and early eighties were of " sufficient" quality according to the MB design engineers of the day. Nowadays the consumer requires higher quality audio.

You are correct. Mine was (is) a budget setup but except for beefing up the power cables, it's not necessary to go nuts with heavy gauge speaker cable for a modest stereo setup. (I might add that cost of all that the power cable runs began to approach what I paid for the $99 bargain components).

The power output specs on your Pioneer and Alpine are still within the capabilities of the factory speakers.

Your fader setup on your 1990 is probably a bit different from mine. For one thing, disconnecting the wires to the fader had no effect on the audio once I spliced into the harness that was connected to the trunk amps. The fader wires on my 1993 are about the same gauge as bell wire, and are color coded red and blue, unlike the speaker wires. It's as if they were designed to send signal commands to the trunk amps to regulate output as opposed to being physical passive connections to the speakers.

Yours should match the wires to the speakers, and once you access the fader, you can splice directly to the head unit. Use the void left by the fader for a block-out panel for a future mp3 player connection...

__________________
2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car