subs in the back

Hi Guys I've searched this thread and gone back to 2007 but hav'nt found the right answer, I have bought an aftermarket radio for my 95 300es I have put the power and speaker plugs in the new radio and all works fine, but how do you wire up the sub woofer in the rear door there is a narrow plug that fits vertically in the back of the old radio this is the line out to the the back door, there is a black and red wire coming from this plug and both going into the screened insulation, the question is are these cables left and right output cables which are grounded by the car chassis, and I can convert to RCA plugs and plug into the line out on the new radio , or is the red one power out and the black the earth therefore I will have to wire it accordingly, also were is the power for the sub amp coming from is from the ignition or do I have to link some cables that are in the multiplug the that feeds power to the head unit as there are 8 power inputs in the factory radio and only 4 in the new one in other words doe's the factory radio switch on the sub amp in the boot. Any help would be appreciated, many thanks.

For the audio make up a patch lead, the head units sub pre-amplifier output + - will be common for a mono sub. so the screens will terminate to the black wire and both the center conductors will terminate to the red wire. The power for the sub amp is from your head unit and is already in the iso plug.

Thats what I did, and there's lot of info on installing head units in the Forum

Thanks for info has any one else have more.

yes you need a remote switch on for the amp it's usually blue or if you dont have that you could use the power Ariel feed as that does the same job and thats usually blue and white the red is power and the black is earth and if you dont have enough power cables to supply it run another power cable to the old wiring from the new wiring

Had this very problem.Connect red and black wires together and connect to centre pin of phono plug that connects to sub out on your radio.
Sub amp has a permanent 12V feed and is turned on and off by the radio in a similar way that it would operate an electric aerial

pauli said:

Had this very problem.Connect red and black wires together and connect to centre pin of phono plug that connects to sub out on your radio.
Sub amp has a permanent 12V feed and is turned on and off by the radio in a similar way that it would operate an electric aerial

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pauli, the sub amp in the back door has two feeds one permanant and one switched.

Hi Discool
Thats what I meant
Permanent 12V and switched to turn it on

Mine was a 300tdi 1995
Yours could be slightly different

pauli said:

Mine was a 300tdi 1995
Yours could be slightly different

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No different

Morning all
First off I got a bit confused yesterday .I looked back on what I did to get my sub working (with Discools help at the time )
The sub audio feed is in fact a whats called a balanced feed that reduces noise pock up on the run to the sub in the back.If your radio has a phono socket sub output you connect the red to the centre pin on a phono plug and the black to the outer (earth) on the plug.This will unbalance the feed but it will work fine.
My aftermarket Kenwood had an aux 12V output that is used to switch the sub amp on and off with the radio
Hope this all makes sense now and apologies for talking rubbish yesterday

Thanks for info but I have two aux outputs on the rear of the head unit.

kindwarf said:

Thanks for info but I have two aux outputs on the rear of the head unit.

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Thats ok, some head units do. mine has three, bass, mid and high. You do know that all the pre-amp outputs are in pairs, left channel and right channel.

good info i just fitted an aftermarket stereo and noticed a spare white multi plug with about 5 wires i think plus the amp multi plug will need to rip back out and wire up then..

When I fitted a Kenwood to mine there is a menu setting where you tell it to output the subwoofer on left ( I think ) aux output

just wired mine up ,put red(amp wire)to elec airiel feed and black to earth,and it sounds **** all muffled and distorted do you think subs are knacked or have i wired it wrong..

Wrong, U have put a power supply into an audio feed.

hi all
i have same prob!!!! dont suppose 1 of you fancys drawing a quick diagram do you ????
PLEASE AND PRETTY PLEASE
KISS KISS KISS
paul

Not a problem For a D1 but a discription and colour code will be easyer as a drawing will take a few days/weekends

So what are you trying to do and what kit do you have.?

i have a kenwood head unit i plugged the power and speaker connections into the kenwood multi plug,then put the red amp wire to elec antenna wire and put black to stereo earth...what did i do wrong..and how can i fix it..i have pro outs for amp at back but havent got the connecters to plug in.

gizgrey said:

i have a kenwood head unit i plugged the power and speaker connections into the kenwood multi plug,then put the red amp wire to elec antenna wire and put black to stereo earth...what did i do wrong..and how can i fix it..i have pro outs for amp at back but havent got the connecters to plug in.

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I take it u wish to connect your Kenwood head unit to the rear door sub amp it that correct.?