VW radio ISO plug connections
Cause of many askings about the original pin assignment of the VW radio plug i created this info page.
This assignment is suitable for VW Lupo, Polo, Golf 4, Bora, Passat 3B/G and other models of these years.
The following picture shows the top view of the ISO plug and the numbering of the pins. These numbers are also imprinted on the plug (where i inserted the numbers).
The assignment:
| Pin number | Cable color | Assignment |
| 1 | blue/white | GALA signal (speed) |
| 2 | green/white | Mute (for telephone) |
| 3 | gray/white | Diagnostic (K-Line) |
| 4 | yellow/red (or brown/red) | Ignition positive |
| 5 | red/white | SAFE positive (only for OEM stereo) |
| 6 | gray/blue | Light positive |
| 7 | red/white | Memory (backup) |
| 8 | brown | Ground |
Some cables may not be available. It differs from extra equipment.
The first part of the cable color is the main color, the second part the thinner line on the cable.
The SAFE pin is a second memory cable. Be careful if you connect a new radio.
Also note that your new car radio does not connect to the K-Line pin. Otherwise you will get some serious errors in your car.
Note that aftermarket stereo may have some different assignment, especially memory and ignition cables. Some manufacturers give the option to swap these 2 cables.
Here are 2 extra pictures from the back.
I can not guarantee the correctness, but i gave my best.
