Electrolux 502 bag full whistle

[corringhamlad]

I bought this cleaner second hand and the bag full whistle has never worked.
I've taken the dial assy apart but it still refuses to whistle. I bought another very cheap 502 at a boot sale and swapped the dials over,still no good!
Any ideas please?

 

[gsheen]

I must have 30 or so of those Electrolux's both Canister and upright with the bag full whistle. I have yet to see one work at all.