If you can't hear the pump working, suspect the fuse may have blown. I've got a 57 reg Astra, and it's fuse number 7 (red, 10 amp) in the fuse box next to the battery. I read online that it's a common fault, and that it should be a blue 15 amp fuse. My fuse blew yesterday, and a mate of my partner's went the other week - so it's definitely a common fault!
Eaglebird, December 2009