Common ground - wireing

[B19]

I am going to install a double din head unit into my 2001 986, but i have a wiring question.

I was expecting to see 2 connectors at the back of my Beck head unit, which i would match up the correct wires from the wire diagrams i have,

BUT on take out my Becker unit i have only 1 connector (power/switched power/antenna control/ground etc) and a yellow connector.

This yellow connector has a +LR/RR/LF/RF, a common audio ground and a 12v switched power.

Where do these get attached to on my new units ISO?

Do i split the common ground 4 times to make it - LR/RR/LF/RF?

Why are these speakers switched?

What do i do with the 12v switched wire from this connector? I'll be using a 12v switched wire from the first connector already.

TIA

[kbrandsma]

By your description, it sounds like you have a CD220 (cassette player) or CDR220 (CD player) Stock Radio and a 4 channel AMP in the trunk? What Option Codes do you have?  M490?

 

The yellow plug contains line outs for front and door speakers and goes to the AMP in the trunk as shown by socket C, upper left hand corner of the diagram below.

 

Socket A (Black Plug 3rd plug down from the top)  The plug contains both switched power - Orange wire, pin 7, from terminal 15, Constant power - thick red/black wire pin 4 that comes from fuse D8  and Ground, thick brown, from chassis, terminal 31. 

 

 

My recommendation is not to cut the factory plugs but purchase pre-made adaptors that will mate perfectly with the OEM plugs. it becomes very difficult to soldier all the connections, crimp them or restore the radio/audio system back to stock.

 

The photo below is courtesy of Pelican Parts. Shown are some adapter harnesses.  For the complete Pelican Article PRESS HERE.

 

Plug A  Connects to the yellow "C" plug on the radio. The RCA plugs in this harnesses connect to your speaker outputs of your new radio and the blue wire connects power up the amplifier from your new HU.

 

Plug B  This plug is the main plug which supplies power to the radio. The ends of this harnesses (out of picture) connect to your new radio.

 

Plug C  This is the antenna adapter for the back of the new radio. (Plug D probably not needed is for iPod FM modulation.)

 

 

 

 

Edited November 3, 2014 by kbrandsma

[B19]

HI,

Thanks for such a speedy reply.

SO i need to get the Socket C wires into a Socket B configuration to wire up the head unit.

Does that mean, i match up the socket C wires to the locations of socket B eg.

Socket C Left Rear line output+ (Pin1) = Socket B Left Rear speaker left+ (Pin 7)

Socket C Pin 2 (RR+) = Socket B Pin 1 (RR+)

Socket C Pin 4 (LF+) = Socket B Pin 5 (LF+)

Socket C Pin 5 (RF+)= Socket Pin 3 (RF+)

Common Audio Ground (Socket C) Pin 3 = split 4 ways and put on Socket B Pin 2, 4, 6 & 8.

Switched 12v power Socket C Pin 6 = Switched 12v power Socket A Pin 7.

 

Is that correct?

[kbrandsma]

No, socket "B" on a Porsche radio are for those from the factory that don't have the option for an  AMP and they don't have door speakers.  Socket "B" is usually a brown plug.  The Pins 3-6 are for the dash speakers and Pins 1,2,7,&8 are for the rear speaker kit.  This option doesn't use the yellow connector. 

 

Door speakers are added from the factory when an AMP is installed and provide the low tones or bass for the system and the crossover is handled by the AMP. Usually the AMP is a four channel AMP, 2 channels for the dash speakers and 2 channels for the door speakers and those that add the rear speaker kit wire directly to the brown plug and let the radio power the doors.   The yellow plug contains pre-amp signals and can't power speakers without an AMP. The common ground from the yellow plug is spliced into 4 separate grounds about a foot or so after leaving the radio.  So coming out of the yellow plug at the radio are 5 thin wires that soon become 8 wires.  The small 8 wires at the plug on the AMP are the yellow plug wires and the larger wires leaving the AMP are the wires that drive your speakers.  There is also another wire coming into the AMP that provides switched power to the AMP.

 

You have dash speakers (front) that are wired directly to the amp and door speakers that are also wired to the amp.  If you want to remove the AMP you will need to either run new wire to all the speakers from your new HU or run new wire from your new HU to the front trunk and connect to that wire directly to the existing wire to the speakers. Don't use the small wires from the yellow plug.

[B19]

Thanks for your replies and patience,

So i think i know what the problem is...

I am looking to install a new stereo in my 01 Boxster, but the Yellow AMP connector (connector C) has a common ground (5 wires for 4 speakers) and my new stereo has (what i've learnt is called) a floating ground (8 wires for 4 speakers). 
How do i connect them together/install the new stereo? 

From what i've researched online i join the negative stereo iso wires together and join it to the common ground wire in the car (which i think leads to the amp).

Does that sound correct?

If so, then i presume i just join the blue amp wires together and put the switched 12v power along side the other 12v switched power cable on the other connector (connector A).

Let me know your thoughts and wish me good luck. I think i'll be trying this on Sunday...  :eek: