I have noticed my air con pump isnt kicking in when i switch the climate on.So i set about checking that power was actualy going to the pump its self.The wire that connect to the pump is dead for some reason .So i then ran a spare oem connector cut from a spare loom to a live feed and the pump started ,but on starting i noticed a sort of nocking /tapping sound that didnt seem to come from the pump but more up aroundthe top of the engine .This sound i guess could be passing through the air con pipes ,im not sure.When i disconected the feed the noise stopped and the engine sounded sweet again.If the air con pumps are nailed do they make any sort of noise.I realy dont want to buy a replacment pump if its not needed but dont know how to completely be sure.