range extender fan keeps starting and stopping

[roogy]

The fan on the range extender has developed a fault whereby it keeps starting and stopping all the time when travelling. It happens all the time whether the car is running on battery or the range extender. Interestingly it only does this while the car is moving. Any ideas please?

 

[mojo]

IMO it's highly likely to be an intermittent fault with a sensor, so probably the best course of action would be to have the car's diagnostic codes read. From that you are likely to see a fault code reporting that a sensor is intermittently out of expected range.