Hi Jeremy,
seems like there are some Mk4 clusters with different behaviour.
Some clusters enable the 3-wire-bus when their coding is above 16000, no matter if there is a radio with CAN bus installed or not.
You have found a car with different behaviour that is more like I know it from the VW Passat: The instrument cluster automatically decides which bus to use. If it sees some message from CAN bus, it ignores the 3-wire-bus.
So only way to make the FIS-Control work in 3-wire-bus mode is to remove the radio.
Actually the FIS-Control can also use the CAN bus. So it does not conflict with the radio. Unfortunately the cable set of the FIS-Control for the Mk4 does not include the CAN bus pins.
The CAN bus support for the VW clusters is not tested by many customers, yet. Most of them don't need it, because the 3-wire-bus works for them. So I would say it is in experimental state.
I also have not implemented graphics support, so you will not be able to show startlogos, boost bar graph, line diagrams and play snake.
If you want to try to connect the CAN bus, have a look at cable set 4 in the following document:
http://www.fis-control.de/files/kabel.pdf
You will see that your current cable does not have the "Info-CAN high/low" connector. You will have to connect the pins 8 and 9 of the green cable harness to the socket E of the FIS-Control yourself.
If this is done, you have to change the setting of your FIS-Control with the FIS-Contol app to "FIS-Control: DDP1.6".