Octavia, MK2, 2005, Engine Bay smaller Fan, cycles on and off.

Has anyone been able to solve this one?

On engine start, after a short period, the smaller of the two engine bay fans, cycles on and off.

The speed of the fan is extremely high.

Both coolent senders and a/c pressure sender checked.

This fan is on regardless of high or low cabin heat selection, or Auto or econ.

The Compressor, Dryer, Condensor and both fans are only just 2 years old.

The A/C low and high pressures are within the correct ranges.

It seems that the larger fan control module regulates the smaller slave fan.

Any help greatly appreciated.