Hi yesterday my car started making a whistling sound through the passenger air vent? Just now i had my blowers on full power and it seemed to do it more frequently this is just with the normal blowers on not air con can anyone help please many thanks

We recently had this in our merc,turned out something was loose in the cabin filter box,so may be worthwhile to have a peek in them 

Usually just a dead leaf or other debris found its way in via the air intake.

so how do i clean this out just by lifting the bonnet and cleaning along the edge?

 

you need to get into the filter compartment for the cabin  also check the fan housing    i think there is a guide on here somewhere in general maintenance 

sorted passenger side window wasnt quite shut slightly embarrased lol