I am upgrading the radio/cassette in my 91 300E 4MATIC. The installation of the aftermarket stereo requires me to run new speaker wires from the new stereo to the amplifier (in the trunk) and an antenna cable extension from the the new stereo to the amp. Can anyone help me with what the best "path" would be to accomplish that?

Thanks!
Mike

I did mine under the center tunnel and then thru back seat into truck. Do a search and you should find helpbul information on this subject.

Thanks for your help, Ron!

A follow-up question:

Since I'd be routing the speaker wires and antenna cable extension via the center console (on their way back to the trunk), is it possible that I would need to run the speaker wires only as far as the fader controler, which is located in the center console? My assumption (and maybe I'm being naive) is all speakers must be connected to that fader controler. So if I opt to not use the fader controler on my new stereo, would I be able to just run speaker wires from perhaps just the output for the front speakers directly to the fader control? (Since I'm no longer using the amp to power the speakers.) I would then leave the new stereo fader control "faded 100% forward" and use the console fader controler of the original stereo system to adjust the fade forward/back?

If that's true, will it be obvious where the 2 pairs of speaker wires are coming into the fader control vs. all of the output wires?

Thanks!
Mike

Mike,

Read the posts in this thread. They will hopefully answer your questions.
http://forums.mbworld.org/forums/showthread.php?t=104353


I did not use the fader control, my tuner has fader and balance.
The stock radio or whatever they call it is in my opinion junk. It’s basically a control unit in the dash, two crappy little so called amps in the trunk, and a tuner/receiver or whatever they call it also in the trunk. I did not and certainly would not recommend using any part of the components I just mentioned.

Also keep in mind that the Mercedes speakers are 2 ohm not 4 ohm like most everything else. That means you need more power to drive them. Hopefully, your radio will have enough power to run the speakers, there are 10 as I recall. You can tap into the 12 pole connects that go into the little stock amps to use the existing speakers. On my installation I had two sets of RCA cables running from the front to the amp in the trunk and then I ran the speaker wire from the amp to the correct wires on the little amps. You might want to consider hooking up your radio to the speakers using the 12 pole connects before you run the wire to make sure the sound is ok with you. If it’s not you will need to get an amp.

Mercedes did not make put a radio in this car easy.

Ron, again, thank you for your help!

Just came back in from the garage... Console comes apart easily. Rear seat removes easily (just heavy). Easy to get to the amp in the trunk. (And I had to be in the trunk anyway replacing my fuel level sending unit ... yea, mine was bad, too. I see from the forums that's not uncommon.)

On the amp, the antenna cable was easy to find (so it will be easy to connect my antenna extension).

But I'm staring at the rest of the wires, and it's not obvious to me which of these are the speaker wires. Okay, maybe it's late. Are the speaker wires easy to locate (at the amp) among the bunches of wires?

Thanks!
Mike

You need a wiring diagram to identify each wire, there are like 12 wires on each of the 12 pole connectors and you only tap into 4 wires on each connector. I have Alldata DIY, that's where I got my diagram, mine is for a 1992 and I don't know if yours is the same. Do you have Alldata? If not consider getting it. I've got it for several of my cars. It's the next best thing to written workshop manuals.

I tried to scan a copy of my wiring diagram but it came out to small to read. I'll try again tomorrow.

On my 1992 there are according to the wiring diagram 10 speakers. One on each side of the dash, one in each door and 3 on each side of the back shelve.

Ron,

I took your advice and just got a subsciption to Alldata for my '91 300E. I see what you mean: this will do the trick for sorting the wires! Worth it!

I do have 1 more question regarding setup. I will be running speaker wires from my new stereo unit back to the trunk as well as running the antenna cable extension. For the other connections the new stereo needs (constant power, power just when the car is on, ground, etc.), can I make all of those connections right at the stereo location in the dash up front using the original stereo wiring OR will I have to run extension wires for all of those back to the trunk as well? Do you know?

Thank you for all of your help. I can't wait to get this old stereo out!!!

Mike

Constant power is to that tuner unit in the trunck, I think it was a 2 prong connector with a red and brown wire, not positive; use a mutilmeter, like a Fluke to check which set has constant power. I did not use that for power since I used a separate amp. and did not want to use that small gauage wire. I ran an 8 gauge wire from the battery to the trunk. I think you could run wires to the truck for the constant power or you could find somewhere else to tap in up front. You could even go directly to the battery thru the same grommet I went thru, only you would have a different route for the wire as it makes its way back to the radio in the dash, that would be my chose since the wire with constant power in the trunk is real small gauge wire. Then you could just ground it with a wire to all those brown wires you see that are grounded to tunnel in the console.

Use the multimeter to find which wire in the dash was the switched power, ie on when ignition was on. I don't remember what the color was or from which connector on the dash unit it was.

Thanks (again), Ron. I think I'm now armed with everything I need to be able to do this.

I'll let you know how it goes and, most importantly, how it sounds. (It can only sound better!)

Mike