Hi

For the past week the pump has been a bit noisy on cold start, but this morning there was no noise at all. Do these pumps run off a fuse or a relay? Ive looked down at the pump it looks all in tacked and dry. Are these units prone to fail? Any help would be great

They generally make the noise because the rivets that hold the two halves of the pump together come loose so you get air leaking out of the gap between the two halves.

If you can get underneath the car take the plastic splashguard off the back of the front bumper so you can see the underneath of the pump and see if there is a gap, if so then just remove the pump (two mounting bolts and disconnect the hoses) and then replace the rivets with some nuts and bolts.

This is what mine looked like:

You can see the bottom two rivets have gone completely.

This is my guide for removing it completely - http://www.pimpmyskoda.co.uk/V2Images/ModsEngine/AirSystemRemoval.htm