[mfevans1]

I had no aircon on my 2010 s40. I bought the car in July so had no idea how the climate control works. When I press air con button to the on position, the green indicator lights up but no cold air. I noticed that the compressor clutch did not engage on any noise from the engine cooling fan....silence. If I by- passed the air con relay the compressor clutch would engage and if the car was moving the air con would get cold (But 'anti-skid service in info panel') . Installed vida and through this software you can switch the a/c compressor as well as the cooling fan at 1/2 speed. The compressor clutch engaged proving that circuit worked. On switching the cooling fan on ..... Silence. I checked to see if the was a supply to the fan (Fuse checked out ok and there was a 12v permanent supply to the fan control module). The fan is fired from a signal from the ecu. This signal is, I believe, a digital one and can only be measured with an oscilloscope. The fan control module is available as a spare via eBay (May be a copy original is a bosch) so I bought a complete fan unit inc. said module from a scrap car via eBay. To test I plugged replacement cooling fan, switched the air con on and low and behold the clutch engaged and the cooling fan came on........aircon fixed. Hope this helps someone.