Stereo wiring on a 1991 GT11

[steamo]

Right I've had my rocco on the road since Saturday and its about time I got a working stereo in there. I've done a bit of wire tracing, dash dismantling and haynes wiring diagram head scratching and I'm still none the wiser.

Its the power side of the ISO plug that I'm struggling with. My plug has 6 wires a permenant live (RED) an earth (BLACK) a dash light live (BLUE/GREY). The ones I can't discern are WHITE/YELLOW and WHITE/BLUE wires which go to the same pin on the connecter and also a BROWN/RED wire. I'd assumed that the WHITE/YELLOW would be the switched live as its the thickest but I've checked it and its dead. Can anyone help identify the mystery wires? Also if the WHITE/YELLOW is supposed to be the switched wire, does anyone know where it goes so I can try and trace it to find out the problem?

Cheers in advance guys.

[ianaudia4]

The car didn't originally come with a switched live, it was permanent. It sounds as if someone has wired a new ISO plug in.

[steamo]

Cheers for that, that'll be why I can't find one then ha.

I'd still be interested in finding out what the other wires are for, they most definitely feed back into the main loom no way there retro fitted. The connector also certainly appears factory, comes straight off the original loom with factory connectors. If anyone has fitted it themselves then they've done an absolutely perfect job of it even the professional installs I've seen in the past make it obvious that the looms been messed with.

Also if anyone can suggest a suitable take off for a switched live I'd be most appreciative.

Cheers again.

[Nate]

you can pick up a switched live at the back of the fusebox. there should be info somewhere on the site about it. can't remember where off the top of my had

[Funky Diver]

Doesn't sound like you have a VW wiring setup on the radio... Brown is the traditional Earth on the year of car you have. The loom may well have been pulled back and new wiring been inserted then the sheath replaced.
Try pulling back the sheathing on the loom where the wiring goes in to find out if that's the case?

You may find that one of the wires leads to the passenger inner arch for a powered aerial so there's another option to check.

I'd be looking at the fuse box for where wiring is run from to get a better idea of what they do. You could also try a continuity test on the white wires with one end of a multimeter on earth and then short out the wire with the other probe. If there's continuity, they "do" something when the stereo is live.

[steamo]

Whoops, don't know why I wrote black, I ment brown for the earth.

I've traced the white/yellow and white/blue right back up to the main loom and I'm positive its a factory connector. I'll get some pictures though for second opinion.

Good call on the continuity test, I did consider the idea that the extra wires may be power feeds when the stereo is on, could't think of what it could be though. Come to think of it is a none standard aerial and there is a cut off aerial lead as well so that could explain one of the extra wires.

[Nate]

1981-85 Volkswagen Scirocco Stereo Wiring
Constant 12V+ Red
Switched 12V+ n/a
Ground Brown
Illumination Blue/Gray
Dimmer Blue
Antenna Left Front
Front Speakers 4" x 6" Doors
Left Front (+) White/Black
Left Front (-) Brown/White
Right Front (+) Green/Black
Right Front (-) Brown
Rear Speakers 4" x 6" Side Panels
Left Rear (+) White/Black
Left Rear (-) Brown/Black
Right Rear (+) Green/Black
Right Rear (-) Brown

Typical Head Unit Wire Harness
Function Typical Wire Colors
Memory / Constant 12V(+) Yellow
Switch / Accessory Red
Ground Black
Illumination Orange/White
Antenna Remote Blue
Amp Remote Blue/White
Left Front (+) White
Left Front (-) White/Black
Right Front (+) Grey
Right Front (-) Grey/Black
Left Rear (+) Green
Left Rear (-) Green/Black
Right Rear (+) Violet
Right Rear (-) Violet/Black

[Nate]

The ones I can't discern are WHITE/YELLOW and WHITE/BLUE wires which go to the same pin on the connecter

i reckon this is going to become live when the unit is switched on. this would be used for switching an amp or a power aerial. plug your head unit in and see if they go live or not.

and also a BROWN/RED wire

i would have thought this would be an ign switched live. bear in mind, some cars / stereos have the permenant and switched lives inverted.

[steamo]

Yeah I thought the same of the WHITE/YELLOW and WHITE/BLUE - just couldn't think of what they were for. Think Funky Diver might be on the money for a powered aerial for one of them.

The BROWN/RED is dead regardless of the position of the ignition switch.

Going to have another play now.

[ianaudia4]

An electric aerial is usually powered by a blue lead, it is in my Storm which was a standard fit, so maybe that is the blue and white.

I fitted a new head unit, an Alpine Bluetooth which is notorious for draining a battery using only permanent live. I took a live switch from the blower switch, sits above the head unit so nice and easy to fit and I have had no issues.

[steamo]

Righto for now I've just wired both head unit positives to the perm live for now. Got some 6x9s off LEEP on here and hidden them under the parcel shelf, relocated the 6x4s from the parcel shelf supports to the doors as the ones in the doors had gone walkies. Sounds fine for now, at least I've got music.

Plan to sort a switched live asap as it drives me nuts having to switch the stereo off everytime I park up. Then run some better quality wiring to all four speakers as well as upgrading the 6x4s hopeing that sould give me some good quality sounds. I am tempted to amp up the 6x9s but undecided as yet anyone know if this will make much difference the head unit seems to power them OK. Oh and need a new aerial aswell as the signal is poop on the existing one.

Still couldn't find out what the other wires do my multimeter broke so couldn't check continuity, I'm still totally convinced that they are factory wires though. Cheers for the advice I'll be sure to post up when I find out what they are.

[Nate]

i tried to find a standard iso pin out diagram, as that will tell you what they should do, but i failed. might be worth a bit of a google?