The standard VDO radio has an option to connect a temperature sensor. Especially in winter it is handy to be able to estimate if it is going to by icy.

For starters, remove the radio.

Then check if there is a hole to route the cable of the sensor through, so it can actually get to the nose of the car. There is a hole where a wire goes through to control the heater. After testing wit a bit of wire it seemed to be large enough to take an extra cable.

The sensor itself is too large to fit through the hole, so it is better to remove the connector from the cable and route the cable starting from the nose to the dashboard. First remove the connector.

Then feed a bit of wire through the hole, hook up the cable of the sensor with some ducttape to the wire so you can pull it through.

Now it is easy to get the cable through.

You can atttach the sensor to the mesh in the nose of the car (it is a bit fiddly though) with a tiewrap.
Then you can connect the sensor to the radio.

The temperature sensor works!