[jb86]

85-92 is mk2
I ran new heavier gauge wire to speakers
Called "streetwires" from crutchfield
It is encased in a clear vinyl tube for protection of chafing
My head unit is out right now
I just checked the wires
Constant 12v+ is red
Ignition switched 12v+ is brown with red line
Ground is solid brown
Illumination is grey with blue line
Those are all easily verified with a test light
The speakers I don't have the colors because I ripped them out
But you could pull each speaker and verify the colors at each so you know what colors you have at the head unit
Besides that
You should get the bentley manual for the car if you're doing any services
The electrical is all drawn out in it
Jon

 

[jb86]

I just re read your post
The jvc plug wiring - you specify red and yellow to 12v+
that's not right
Red should be 12v+ constant - always has power, saves memory and clock
But yellow should be switched, actually on my car when key is inserted. That turns on the stereo
Then you have ground which is black to Vw brown (all the grounds are brown)
The illumination when you turn the lights on - mine is grey with blue line
Test all of these
Touch the negative of your test light to the brown, positive to the red, it lights up
Then to the brown/red when key is inserted it lights and goes out when key removed
To the grey/blue goes on when park lights come on or off when they go off
Be sure you get positive/negative correct on speakers
Better off to get better quality speakers though
I use crutchfield, they save a lot of grief
For a test light I use a 12v red led from radio shack and solder wires to it and put an alligator clip on negative. Led is safer for computer in car according to bentley manual