I was researching something else and happened upon some posts about this. Buzzing noises etc. I was like wtf? Never heard it on mine, so decided to investigate. Made sure everything that could make a noise at ignition on was turned off except the obvious chime. Put my ear right on the little vent to the right of the (LHD) steering wheel = NOTHING, no whirr, buzz, flutter.

Some posters on the other problems with this component said to carefully pop the little vent out and clean out accumulated fuzz, debis, dirt. So I popped it out and it was full of junk. Cleaned it out, tried listening again, and low and behold there is a faint impeller sound. Mine is so quiet that you literally have to place your ear on the vent to hear it working.

But.....Here is something unexpected = my A/C has been pretty good with occasional very brief periods of not quite as cold (in 100+ degree heat drving). Since cleaning out that little nuisance, constant cold flow!

Weird, but worth a try for some others.