Some Brabus Roadsters appear to have a manufacturers wiring fault.
Namely the chargecooler fan spins the wrong way.

The fan (as standard) blows air into the radiator (clockwise rotation), but because it is a rear mounted fan it is forcing air against the natural airflow through the radiator, reducing its efficiency.

It is clear that the intention from smart/Brabus was indeed to have the fan sucking the air through the radiator (anti-clockwise) to compliment the natural airflow. The 'rotation' sticker on the fan casing would also suggest this was the case.

 

There are other potential issues with the fan running the wrong way, and that is the fan will now 'push' debris into the radiator, potentially flattening the fins.

It is possible to swap the wires with the radiator in situ.

Alternatively you can remove the fan to view any potential damage.

The current wire arrangement is Blue->Brown and Black->Yellow.
The correct arrangement is Blue->Yellow and Black->Brown.

The connector is located above the radiator, just under the subframe.

There is a single clip on the connector, just press this in and pull the cables apart.

Use a thin scredriver to just release the tabs on the cable retaining clip.

Again use a thin watchmakers screwdriver (or paperclip) to release the retaining pin on the blade connection itself.

Gently pull on the cables at the same time.

The wires should now be free to be removed.

Swap the wires over, and press back into the plug, they should secure themselves into position.

With the wires clipped into place and the blades are straight in the connector, clip back into place the cable retaining clip.

Now the connectors have been changed just clip back into the main connector in the car.

Reattach the fan (if removed) using this guide.
Thanks to Jeff Hall on the smartclub for bringing this to our attention.